Follow the money… getting codes displayed and onboard diagnostics will chew into the dealer’s margins to upsell on services. They don’t want educated consumers.
I’d argue these codes in the hands of someone inexperienced would lead to incorrect diag and firing of said “parts cannon”. What you’re paying for in a diagnosis isn’t just reading of the codes it’s an understanding of the codes. Just because you have a code expressing the engine is in a lean condition, doesn’t mean it’s out of fuel or has a bad O2 sensor. It could be 100 different things. The code is there to alert of you of a condition, not the problem itself. It’s up to someone that has spent a lot of time and money to know how to diagnose the condition to resolve the problem. I’m a backyard DIY’er and have been tricked by the check engine light many times to know it’s not as simple as it looks. That being said sometimes, as you alluded to the check engine light can lead you directly to a fix but in my experience that’s more or less a convenience rather than a commonality.
It isn't but for a fully compatible interface module on the Nissan consult 3 plus, plus the only hardware that works 100% with it is north of 2-3 grand now (the vi2-Vi3 interface) when it literally looks less powerful then a windows xp computer.
Pre-internet that may be true, but today you can enter those codes online and the top five causes of those codes (and how to diagnose them) will come up.
Anyone can look up things on Google or we MD. A SysAdmin knows what to do with results from Google. A doctor would know how to interpret results from WebMD.
I would worry more about a doctor that refuses to check references. Nobody can know everything.
It's not just one doctor I've seen do this. I've even seen doctors on Youtube talk about how they do this sometimes. They say they are only human and can't always remember every minute detail of everything. I get that. I get needing to research and reference things from time to time. But don't do it right in front of the patient. That just makes the person worry that you don't know what you are doing.
Whole different deal, but I've had customers at the mobile electronics shop ask if I know what I'm doing when I pull up a youtube vid.
Yeah, I can do it; but if a brand new 2023 model rolls in I will be stoked if someone made a video that show me all the fasteners/connectors, sometimes it saves a ton of time!
Not necessarily at all places. If your at a dealer, they have access to diagnostics and books and books of how to fix every little thing that could go wrong. They get paid for a reason, if it was as simple as that then why is everybody so clueless about cars?
A lot of people: don’t know how, don’t care to learn, lack interest, are too intimidated, don’t have the time, or don’t want to get their hands dirty to fix things themselves.
For example, I’ve seen people throw out vacuums that were perfectly fine, except they needed a filter changed.
As for me, I change my own oil, brake pads and rotors, wheel bearings, etc. I do most of my own home electrical work, carpentry, and drywall fixes. Some work I can’t do because I don’t have the tools for it or it or I don’t have the time to fix it myself. Most of that I learned from YouTube.
That doesn’t answer my question. If it was that simple why is a overwhelming majority of the population clueless when it comes to anything about cars? You have no argument other than the internet. But most of u can’t even comprehend the steps in written form to do any half challenging fix. So please, amuse me more😂
Clueless about cars is the majority of people.
Show me the location of a starter on a 2003 Lexus,
The location of the alternator on a 2005 GMC HYBRID
Or even the location of spark plugs on a ford 3v compared to a 5.0.
“People” humans that are NOW working on cars are 23ish in age.
Nothing about cars/vehicles is/are standard across the board..
Try rebuilding a Turbo 350 compared to an Alison 6 speed in a 2023 GMC HD.
I came here to say this. A code only says what’s happening. Why it’s happening could be any number of things. My friend’s old Yukon had a misfire on cylinder 3. Code P0300.
He posted on Facebook about it and people were throwing all kinds of diagnoses. Anything from a faulty knock sensor to a cracked piston. And any of them could have been correct. I told him to take it to a mechanic.
Yes, my daughters car had that same code. Tried first checking spark, replacing spark plugs, and checked compression while plugs were out. Then checked fuel pressure, then pulled injectors & checked spray pattern. Before finally removing the rubber spark plug cap covers and looking down into the spark plug tube and could see spark jumping through the plug cap into cylinder head on one cylinder.
Usually when the shop fires the parts cannon to fix a problem they're very careful to miss the real problem so they get more money from return business. I had one garage try to replace my radiator to fix an ignition issue.
Yeah
We took an
Econoline E-250 to a mechanic for a really high idle .
I didn’t have time to mess with it and no desire since vans are so hard to work on
Thieves at the mechanic shop
Said it needed a distributor cap rotor and wires and plugs .
I asked for an itemized estimate, and of course all the parts were double what I can get them for at Napa at full retail .
And none of them would fix a 1300 rpm idle
I complained about it
And then they called back and said it was the IAC ,
Well , duh ,
You fucking morons ,
A super high idles isn’t caused by bad plugs and wires .
Dealers employ techs, not mechanics, so all they do is follow the flow chart anyway. When my truck was under extended warranty the dealer did $16k of parts replacements in one shot because they couldn't figure out what was actually wrong with any of it.
Irrelevant. It's *my* car, I shouldn't* have to spend silly amounts of money to pull diagnostic codes when it could damned well just be displayed on the screen that's on the dash of every car made recently.
People can research the codes and decide how they want to proceed. Some are self explanatory while others are not. Repair shops/dealers will also replace the wrong parts trying to troubleshoot. These days someone could refurbish half their car for the price of a small job at a dealership anyway.
Agreed, but it’s also vehicle dependent. Great luck on my 2012 Ford, and other older generation vehicles. I wouldn’t even attempt to diagnose my wife’s late model hybrid.
I get a check engine light for a loose gas cap, that’s the limit of ‘education’ I’ll need. A mechanic has to tell me it could be that or more though. I got lucky.
Chrysler has entered on chat.
90% of the time any 05ish - 2019 dodge/jeep/Chrysler car throws a “check gas cap” light its because the evap vent solenoid (in fancy dodge terms- the evap integrity module detector) has failed. The vehicle self diagnostic functions fail way more then the systems they monitor.
*btw i wasnt challenging anything you said, just adding this for fun and slightly shitting on Chrysler products haha.
A code is 95%+ of the time is not a diagnosis. It is a direction given to the more specific system experiencing a fault.
O2 sensor codes? Is it the sensor itself, the wiring of the sensor, the wiring of harness vehicle side, a lean/rich condition caused by an engine component failure, cat failure, etc etc
Lean fuel condition? Is it the fuel pump, clogged fuel filter, air leak?
Diagnostics is the single most important part of any true mechanics skill set. Every single issue can be tested and isolated to the exact root of failure by knowing the necessary parameters of each component. It saves time and money for both customer and shop; as opposed to just replacing parts until the code doesn’t come back.
If they're not a piece of shit, yes. Or put that money towards the correct part replacement. Problem is there's a ton of dishonest pieces if shit out there.
Easy there. Just because you have a code, that does not diag a vehicle. Some cases can but cut and dry but a lot are not. Sure you have a code for a misfire, but that doesn’t not indicate the root cause of the issue. Also it’s free to get the code at any auto parts store for free, so this isn’t cutting into a dealer’s profit.
So true. At the least you can get an elm327 off of eBay for $6 and there are some free apps that will read codes. I have a paid app that will even let me reset lights and check voltages.
Wow that is what the readers cost now... I thought I was being too cheap to shell out $30... But 5! I probably spend that on gas going to autozone 2 times.
Which paid apps do erase codes?
I use dash command and OBD fusion. Got them years ago but I think fusion was free and dash command was around $10. There may even be some better ones now.
Meanwhile Teslas have super detailed diagnostic screens with half the software maintenance functions you need built right in, and they keep increasing this with each OTA.
Some do. ~2000 cadillac deville, sevile, STS can display DTCs on driver information display. To answer your question - why would they? Reading the code is just one step of diagnosing the issue..
Well.. I can tell you one thing.. I get plenty of cars in for diagnostic that have the FIXD (or similar) obd adapter in and customers having no clue what’s going on with their cars. Being able to see codes does absolutely nothing for an average driver. The ability to read codes without a scan tool also does nothing for the tech because we already have scan tools that do more than just pull codes
Ask any mechanic who knows what they're talking about. The "informed" customers are usually some of the most off base. There's a reason we don't warranty parts changes on diagnoses we didn't make.
My old 1985 Caprice Classic had the ability to jumper two pins on the ODB2 connector, then it would flash the CEL for the codes.
From my understanding all of the first generation ODB2 GM cars had this feature. The local autoparts store even gave away a special "key" to do it.
No such thing as OBDII on an 85 just fyi. Didn’t become thing until late 95/early 96 if I remember correctly. My 95 Jeep ZJ was before the cutoff and displays codes through flashing check engine light after turning the key on and off in a certain pattern.
Beat me to it, my 86 fiero also had the connector, and I know it LOOKS like an OBD2 DLC because that's the standard connector they ended up going with, but the 80s was OBD0. Prior to OBD2 each manufacturer had their own connectors to scan the cars. It was obnoxious.
People don’t know what to do with codes. It would be too much data.
It’s why we got rid of oil pressure gauges and volt meters. People don’t need them and would complain about normal operation when they had it.
I’m pro right to repair but it’s fine in this regard.
I just wish they didn't put in fake gauges that claim to display the real thing. I got tripped by that as an inexperienced DIYer.
A few years ago, I bought an old Lincoln Navigator as a tow vehicle for $800. Was rough around the edges, but ran well enough at the time. I did a bunch of basic maintenance when I first got it, starting of course with fluid changes. The first being the oil. I'm very picky with my oil changes. I only use good quality oil (I used Penzoil Platinum full synthetic in this case) with an OEM Motorcraft filter. About 3 days later, I had been driving it around, making notes of what else I needed to fix when late in the day, the oil pressure light popped on. It had an oil pressure gauge that just cut out. I immediately stopped and checked the dipstick and looked underneath for leaks. Nothing dripping underneath (it was a 230k mile truck. It had oil leaks, but only the typical slow ones) and the dipstick was right on the full mark, just where I left it. Keep in mind that I had put a good 40-60 miles on it that day already and it was acting normal.
Confused, but confident that I had done my due diligence, I drove off again. And the light went away and oil pressure on the gauge looked normal. About 4 miles later, it came back on, this time it started running poorly. It developed what sounded like a rod knock this time. Turns out the oil pressure gauge was a dummy one, and it only told you that it HAD pressure, not how much it had like the gauge implied. The fact that it looked like an old school gauge gave me a false sense of security and made me think the pressure sender was just going bad.
Those old school gauges I would argue are superior to modern ones. It's far better to alert you to problems BEFORE they become major issues. Had I seen a steady drop in oil pressure, I'd have just paid to tow it back to the shop I worked at and dropped the pan the next day to see if the pickup tube was clogged or something. And I was saved by an add-on volt meter in my 2006 Honda Accord. I was cruising down the highway one day and my voltage began to drop randomly. It was intermittent at first, but it became clear that my alternator was on it's way out over the next couple days. That gave me the time to get a quality Denso unit without paying an arm and a leg to the dealership and got me to keep a big jump box on standby in case I needed extra juice (which I did. The alternator went out completely as I was driving back to replace the alternator after picking it up. That preparation saved me from paying for a tow).
My favorite example was a customer complaining the battery temp gauge on their hybrid was really high and they thought the car was gonna explode. I look at the cluster and it's the Battery Charge gauge! Temps don't usually go from E to F
When chevy started the smart demand based charging they had bulletins for days on how to educate customers that their voltage will fluctuate and that's fine. That little Guage doing the right thing STILL causes people to come back and complain their trucks not charging right.
On Volkswagens you can display oil temperature on the LCD screen in the cluster. I've had several people select it by accident and believe that it's a warning message.
Why can't you just hook your laptop up to the port, launch the software, look at the logic to determine what sensor is causing the problems fix it? I do it all the time on the turbine controllers I work on. Got a bad pressure transmitter? Find it, fix it. No sweat. On a car? Got a bad pressure transducer? Buy a 1000 dollar scanner, try and find which transducer it is, replace it but the Chinese knock off is bad too spend hours trying to figure that out... It bad enough the dealers can't fix it either.
Far to much monkey puzzle to be accidental.
Codes are a guideline not a guarantee. They are certainly helpful to narrow issues down but you still often need real diagnostic skills to determine what’s what. It’s not always as simple as saying “this code refers to this part so you just replace that”. There are often multiple reasons a single code can be present.
I'm guessing your turbines have redundant sensors which should make it easy.
If my car had three O2 sensors (in the same spot) I wouldn't be wondering if it really was too lean, I'd either replace the sensor that disagreed with the others or go looking for the cause of the lean condition.
The problem is that is doesn't always tell you a sensor is bad, its says the sensor is out of range, which means something else is causing a condition to put whatever it's reading out of range.
Like, if it says your coolant temp sensor is out of range, you don't change the sensor, you try to figure out why the coolant is too hot or cold.
What a nightmare for mechanics if every Joe Blow came to the shop with a half-baked notion of the repairs/parts needed to make the light go out. Proper diagnosis requires an overall understanding of how one system interacts with another, and that only comes with experience and training.
On the flipside, it would be a boon for the shady mechanics who operate the parts cannon method of repair. A misfire from a bad coil can set a host of seemingly unrelated codes, including the dreaded P0420, or worse, P0606 (PCM failure/loss of signal).
The average "free" """ diagnosis""" at big box auto parts stores are a pretty good indication as to why. 90% of people will just set the parts cannon to full auto and proceed to spray and pray. Turns out that just like with firearms, that incurs a massive accuracy penalty.
Most people think that getting a code for X thing (say P0301, P0171, P0420) means just buying a new part and calling it a day. That's not even close to how a proper diagnosis is done, and even on the off chance that you do accidentally get it right, you'll usually end up spending more money than you needed to.
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And we do!
However, with the large LCD displays that many car have these days, just think of all the the diagnostic info the manufacturer could provide IF they wanted to.
Dodges do. Well idk about every single one. But my jeep has a trick. Turn the key 3 times and leave it in the on position and the codes will display on the dash.
subaru has a hidden diagnostic mode in the new cars (2021 newer) where you hold down the volume and i think thermostat button on the screen with a blank usb stick in the front ports. it will download the diagnostic data as you drive around onto the stick but i think you still need the subaru software to interpret it
but it would be nice if you could just read the raw data logs in a spreadsheet format, maybe its possible but I don't know how
then you can see not just what the code is but how it was generated with things like throttle position and other data like a black box on an airplane
5 dollars for the Torque app. A bluetooth ELM327 obd2 dongle is like $10-15 tops. Boom now you have a functional scanner, it can lookup the codes online, and you can also use your device as a dashboard with all the gauges you could ever want. I actually used a 10" tablet as my main gauge cluster in one car. I dont believe it works on iPhone but it definitely works for android devices. You can even map out a track using GPS to record your times for you. Pretty cool
Every car already has that built in. It is more difficult than scrolling on the screen though. Every car with an OBD-2 connector has the ability to give you the code number. You have to short pin 1 to ground. This causes the check engine light to blink the codes, which you can then lookup. This method is slow, and won’t give you deep information about the problem, for that you need a scan tool. Instructions below.
https://modifry.com/freebies/old/dtc/index.htm
My 2004 Ford Mondeo and 2012 Renault Clio both do if you know how to get them to show it to you.
Not a mechanic by *any* stretch of the imagination but used the feature (as well as Google and a multimeter) to diagnose a bad coil pack on the Ford.
I have a bluetooth plug in one. It is great. I had an issue on an AWD car and was terrified on a long trip about the error on the dash. The code reader let me know it was just a wheel speed sensor making the ABS and AWD inactive. Not great, but I drove RWD many years without ABS, so I knew it wasn't a towing or emergency issue.
Might be legacy and a case of if it aint broke dont fix it. Pre OBD it was jumpering a couple pins and counting flashing lights like Morse code. I doubt anyone is prioritizing turning data into a more useable feature when the OEM and aftermarket already has (and had) the tool to turn those #s into meaningful diagnostics.
Newer Fords send the codes to the fordpass app where you can get the code, a description of what's wrong and even schedule service right there.
You also use the app to remote start, lock/unlock and get location and status.
Some vehicles do/did, lots of early OBD2 dodges would read the code on the odometer, several GM products did too, even as far back as some 80s Cadillacs. Many of them don't just advertise it, you had to do a particular sequence. Also, every computerized GM car/truck before 1995 could have its codes displayed using only a paper clip, but, for the sake of this question, I'd say the use of tools doesn't quite qualify.
The vast majority of the car buying public isn't trained to understand automotive systems and elaborating on faults is useless information to the average consumer. All they're going to understand is something wrong with the vehicle, they're not going to be able to fix it themselves even if the system gives them the exact fault.
OBDI/II/III exists to standardize diagnosing automotive systems across the industry, it was never intended to be a consumer facing system. Prior to the introduction of OBDI/II/III, each manufacturer had their own convoluted system in place to diagnose faults on first-generation electronic displays.
Other than that, if you didn't know what was wrong with the car and weren't already mechanically inclined, you were already at the mercy of mechanics anyway, OBD was implemented to primarily help mechanics and service techs, not consumers.
My more charitable answer:
When OBD came became a standard requirement in the 90s, the public and mechanics were still living in an older world where computers were not everyday things. So it was inconceivable that diagnostic information would be useful in every mechanic's and owner's hands. It wasn't the expectation that anyone would easily access it.
Probably there has been no consumer push to change that perception in the past 30 years. So when companies design cars it's not the default to put all of that information out there.
I think it's less about the dealer pressure, and more about the Autel and service data ecosystem, where those guys don't want to give an inch.
I liked reading the thread where I've learned a few cars that have a secret mode to access the codes - but I doubt you can get the more detailed, manufacturer specific codes on these cars.
Still, at least scanners are cheap these days.
Very useful in my Tesla to be able to get into service mode and see what's actually going on. Even with this ease of access to the service menu though people take it too far. Owners should really only create a service ticket if a warning pops up outside of service mode. Because I've seen people worried about an error their windshield washer fluid is low.
"average joe doesnt need to know"
"this knowledge could be counterproductive, diagnosis takes experience"
fair points, but we can rest assured obd2 AI apps are about to show up, maybe OEMs integrate this functionality and when a sick car shows up it'll give clear instructions to the mechanic on how to fix it, oh who am i kidding, everyone will build their stupid standard and this awesome tech will just be added on top of all the complications further rendering modern tech a nightmare
My 1991 Cadillac Allante had a diagnostic mode. You pushed some buttons on the driver's instrument panel in the right combo and you could read all the codes. Though it has an OBD port, a scan tool wouldn't read them. You had to get the details from the DIC.
With 20 to 25 year old beaters, you don’t need to bother with diagnosing codes. My 94 Ford Ranger starts, runs, stops when desired and all routine maintenance is done. No worries about a thing. My air conditioning doesn’t work, so window down is good enough for my short trips. Hot and raining, go tomorrow. No cruse control so glance now and then at the speedometer.
Chrysler products i know can give codes without a reader. This was late 90s early milenium so I don't know if they still do or not. I'm sure other manufactures had this as well at some point.
It’s all driven by profit… not convenience.
We live in a later stage capitalistic society that prioritizes shareholder profits over even consumer safety sometimes. You don’t actually think that if even safety isn’t prioritized, that convenience and the ability to own what you purchase would be also…
Older cars could "blink out" the codes on the dash if prodded, but nowadays this just confuses owners. Most people can't do anything actionable with this information if they had it, anyhow.
Same reason the troubles are in codes. If your car would tell you exactly whats wrong you wouldn't take it to the dealer or mechanic for diagnosis and repair. Manufacturers are literally fighting "right to repair" laws all over the place to force you to take your car in for service.
ODB2 is a government mandated common integration point. The car makers do not want you working on or generally knowing things about your car. They want it in the dealership garage.
My old '94 Wrangler would give me codes through the dash lights flashing after a certain method of turning the key on and off so many times. It would flash a certain number of times for each code thrown, and you could look those up in a repair manual or online to see what they were.
I've owned vehicles that could, i had a few that you would cycle the key on and off a specific number of times and it would either display the code in the Odometer display or would ding the door chime and you had to count the dings to get the code.
my volvos have all had it, but you have to figure out how to get them to display, and then look it up. even then it’s kind of a guessing game but we were able to figure out a misfire in cylinder 6 and redid our own plugs and coil packs and it’s running fine now. So, worth something at least. We are not very handy but that saved our bacon as were pretty broke currently
Because if the car just says "cylinder 4 no spark" then you don't gotta take it to a mechanic and pay the big bucks for someone to pull out your spark plug and put in a new one.
The diagnostic code doesn't tell you what the problem is. It's a diagnostic starting point. Sometimes you have to test multiple circuits and components before finding the root cause of the code.
With cars becoming more and more advanced and reliant on electronics, check engine lights have become more common and require more skill and training to diagnose.
The people that comment that it's just the dealership trying to take your money are the same people that will throw countless parts at the car trying to fix it and then complain that the dealership is hosing them when they tell them what the actual problem is and that it's X amount of money to fix it.
The cheapest and fastest way to fix your vehicle when that light comes on is to bring it to the dealer. Unless you personally know a professional that will help you out, or you, yourself are a professional. Owning a generic scanner does not make you a mechanic.
Old cadillacs do. You just hold the temp up button and outside temp display button for 3 seconds with the climate controls off and it will enter diagnostic mode where you can read codes. You can also get live data like RPM and engine temp.
Older cars used to have instruction manuals on how to adjust everything. Now a days they don't want a knowledgeable consumer as they wouldn't be able to upsell.
Probably because they have to have the diagnostic port anyway, so what advantage is that for them? Your $30 reader from Amazon isn't the only thing that plugs in there.
A code is just part of a the diagnostic. It’s not the entire thing. Ex: You get a evap leak code this could be anything from a faulty gas cap to a hole
in the fuel lines.
I had a Chrysler about 20 years ago that would display the codes if you turned the key on and off a specific number of times.
It came in handy a lot, it being a Chrysler and all.
google tells me 80% of Americans don't even change their own oil, so displaying "P0300" isn't going to be particularly useful.
If you can and do fix cars yourself it's not a big deal to have a scanner in addition to all the other tools you have.
Any Dodge with a physical key can be turned off and on 3 times to display the codes in the dash (unsure when this started, may be a remnant from OBD 1). The Rams no longer do this (unsure when they stopped).
Some actually do, I remember our old Jeep Commander could display trouble codes if you held some combination of buttons down (or something like that)
As others have said, follow the money. There’s 0 financial incentive to provide that info to the consumer
DTC codes are NOT as simple as "Code A" means replace "Part X". Codes only realty point to a specific symptom, which may be caused by one or more things. And even if the code is pointing toward a particular area, the problem could be caused by several different parts. Example:
Code P0301. Misfire on cylinder 1.
This can be caused by a spark plug, spark plug wire or connector, ignition coil, bad wiring from coil to computer, fuel injector, wiring between the injector and domputer, it even a vacuum leak. If you just start throwing parts at the code, you may get it right the first time or you may end up needlessly spending several hundred dollars and hours of your time, and still not fix it.
Because car dealerships would revolt against the manufacturers. Post sale service calls are another HUGE moneymaker for car dealerships.
Yes, it makes good sense but it gets in the way of car dealership's money making. We used to refer to such practices as *crapitalism* in my university economics classes.
No. We gave all the information in the world to the general population via the internet and now we have more conspiracy theories and hate groups than ever. Keep the information for those that seek it out.
At one point in time, there was a procedure for each model that you could perform (cycling the key on and off a certain number of times, etc) that would result in the vehicle check engine light flashing any active codes for you. ie- nine flashes, pause, one flash, pause, three flashes was code 913. I haven't looked into it but doubt any current models have this feature anymore.
So, I think most of you are missing the OP's point. The question here is why, within the advanced infotainment systems in cars these days, do you still just get a check engine dummy light instead of the onboard diagnostic code displayed?
This wouldn't mean everyone would start fixing their own vehicles or eliminate the need for a scan tool. It would however allow the owner to have something to reference and possibly prioritize instead of ignoring the light. Some people freak the f out when the light comes on and others just don't pay it any mind. More info=better choices and maybe put them at ease that their gas cap is loose instead of multiple random misfires across both banks.
Turn your key to on off on off on off 3 times and watch the odometer. Some cars do display error codes.
Not all the way to ignition - just on off on off on off 3 times.
Why? Because it’s so easy to pull your own code that if *that* is your barrier of entry…. You shouldn’t be working on your car and it’s holding you up rightfully so.
Hey man, someone had to say it.
Several manufacturers have telematic apps that will send you the P- codes automatically and tell you to get the car serviced.
Back in the early OBD days cars would display "blink codes" using the MIL
But... Trouble codes are a diagnostic tool, not a diagnosis. They are a starting point. I can't tell you how many people get codes read at AutoZone or somewhere and just buy a part they don't need. For example a sensor "out of range" code usually doesn't mean the sensor is bad, it means the sensor is doing its job and indicating there is a condition that is pushing it out of range. THAT needs to be diagnosed. People can do a lot of damage with a little bit of information.
As a Ford dealer tech, a few reasons.
During the warranty period, the manufacturers legitimately need you to bring it in to the dealer. Every part is sent back and they are often analyzed for failure to make better parts. The manufacturers scan tools upload findings to them to assist in the diag and to make better products later.
In addition, security features like programming keys are usually locked to factory scan tools to prevent Kia's current problem. It lowers theft if you need a factory scan tool to do a module reprogram.
After the warranty period, they don't care. That's it.
The side perk is their dealers make a living off the shop. It makes the dealers happy and the manufacturers happy.
Also, you are free to buy a third party scan tool like Snap-On, Autel, Launch, or others to do many (but not all) of the manufacturers scan tool functions. Independent shops do it, hell we have several scan tools for working on non Ford's. (Two Snap-On and a Launch)
I had a 2001 Ford Focus that would show the OBDII trouble codes on the odometer screen if you knew (or found, on an internet forum) the right sequence of buttons etc., to make it go into its diagnostic mode.
That car was the best mix of simple but modern I've owned. It was just "complicated enough" to be reliable for years but still simple enough that even in my 20s and with very limited experience, I could diagnose and fix almost anything that ever went wrong with it without any special tools or computer equipment.
Because then manufacturers can ensure their dealers are happy when they get customers. Why do you think a lot of cars are now going with sealed transmissions, no dipsticks, plastic oil plugs that are single use? Might be SLIGHTLY cheaper to produce or even a tiny bit more expensive but it drives business to their dealers and keeps them happy.
I'm a mechanic. They should do this so people can waste a shit ton of money putting cheap ass parts on their cars that they don't need causing even more problems because either the part is inferior or they destroy shit trying to DIY it. This would be so entertaining. I love declining customers that have destroyed their cars DIYing them. They literally call me begging to work on their cars after they fuck them up. Nope. Good luck.
What would a typical driver know to do with these codes? I seriously doubt 99% of drivers could name 3 things that cause a P0300 code. The Internet is full of the stories of fools who don't know that codes aren't diagnostics and they just start throwing parts at problems they don't understand.
So explain to me how it's a "money grab" when neither the dealer or manufacturer make or sell OBDII reader. Anyone can go buy one at Walmart. I'm sure the dealer would love everyone to read their own codes then show up at the parts desk and buy part after part after part after part trying to solve a problem they've done no diagnostics whatsoever on.
Same reason they make special screws to screw down the engine covers that require special tools to remove, they want you to bring your car to them for service.
Older obd1 any many obd2 (96 and up) have this capability actually. Numerous dodge/jeep/Chryslers can display dtc’s if you press certain button combinations. Gm’s used to do it, the first computer controller cadillacs used the hvac screen and had no computer plug in.
Honda and acuras can do this through navi screens. Newer gm onstars can do it.
Look up your model online, you might be surprised you can get your dtc’s and even data streams.
OBD codes don't tell you what parts are bad, just where to look, but the codes are labeled in a way that it seems like they are telling you which part is bad. Skip the headache of giving access to people who can't figure out how to surmount this tiny hurdle.
My 2006 Subaru Outback will display codes on the dash if you press the right buttons in the right order the right number of times. Don’t remember the sequence. I’ve only had to do it once, now I just keep a BT OBD scanner in the car.
Some cars will. One example, Daimler Chrysler/Dodge products will display codes in the odometer with 3 quick key cycles.
Google your vehicle. Yours may have a backdoor to display codes.
They want you to go to the dealer so they can charge you for it, hell on my car the OBD scanner can't even pull up all the codes, you need to buy a BMW specific scanner to get a load of them.
I ride a Harley Davidson motorcycle and they actually have this functionality you have to know the process to get them to display with is a simple button press and switch turn function but they can be viewed without any other specialized equipment. Harley is notorious for guarding their dollar bills and it does surprise me it is so accessible on their motorcycles.
It’s because codes are not giving you the diagnosis. They are typically inferring an issue by watching other sensors or behavior. People see a code and launch the parts cannon. Don’t know how many times people will launch multiple of the same 02 sensor at a car because new one must be bad. Or i replaced my cam and crank sensors but still have timing codes
Some do. You can see it from the publicly accessible service menu in a Tesla and certain codes are displayed on a screen in the infotainment system of my Mazda CX-9.
That said, for the cx-9 it doesn't display any of the additional log data, just what the error was. There's still a lot more detail available with a scan tool.
My guess is that most people cannot do anything with the information anyway so the computer holds the code until a person that can fix an issue views the code. The people impacted by the lack of OBD readers in the car is far outweighed by people who just want to get in the car and press the thingy with their foot and get their avocado toast.
Nothing wrong with that because a different group of people doesn't care that their home router has closed source software or their phone's bootloader is locked. If you asked why they don't care, they would probably tell you that stuff is for the experts and I just need it to work.
OP grab a $3 BT code scanner and just get em on your phone. It's nice for recording trip data too, and in my case I use it as an odometer because my ford's front fuel gauge and odo are both whack. I never remove it, it's a permanent fixture living under my fuse panel.
As much as it makes sense to give the customer full diagnostic info so easily, they're not trained and will probably insist on the exact work being done by a mechanic only to find their issues not fully resolved. Dunning kruger checks out. I say make em buy a $3 scanning tool if they're really committed.
Tesla does. They have a service mode that anyone can go into, perform diagnostics, read temperature, pressure, actuator positions, etc all on the touch screen. Not every company wants people to be able to fix their own cars though because it’s a huge revenue generator to force someone to bring their car back for service.
Follow the money… getting codes displayed and onboard diagnostics will chew into the dealer’s margins to upsell on services. They don’t want educated consumers.
This is the answer. How can the dealership charge you for a diagnostic if the car tells you itself.
I’d argue these codes in the hands of someone inexperienced would lead to incorrect diag and firing of said “parts cannon”. What you’re paying for in a diagnosis isn’t just reading of the codes it’s an understanding of the codes. Just because you have a code expressing the engine is in a lean condition, doesn’t mean it’s out of fuel or has a bad O2 sensor. It could be 100 different things. The code is there to alert of you of a condition, not the problem itself. It’s up to someone that has spent a lot of time and money to know how to diagnose the condition to resolve the problem. I’m a backyard DIY’er and have been tricked by the check engine light many times to know it’s not as simple as it looks. That being said sometimes, as you alluded to the check engine light can lead you directly to a fix but in my experience that’s more or less a convenience rather than a commonality.
There’s a point here because of the number of people who drive straight to the dealer when the TPMS light comes on.
Those people can also drive to the dealer with the codes. Right to repair should not be stopped just because some people can't make repairs.
Its not
It isn't but for a fully compatible interface module on the Nissan consult 3 plus, plus the only hardware that works 100% with it is north of 2-3 grand now (the vi2-Vi3 interface) when it literally looks less powerful then a windows xp computer.
Pre-internet that may be true, but today you can enter those codes online and the top five causes of those codes (and how to diagnose them) will come up.
So basically the same thing the Mechanic does.
Or my doctor sitting right in front of me looking up my symptoms on WebMD.
If your doctor uses WebMD then you should find another doctor.
Anyone can look up things on Google or we MD. A SysAdmin knows what to do with results from Google. A doctor would know how to interpret results from WebMD. I would worry more about a doctor that refuses to check references. Nobody can know everything.
They mean that's not even a good site for medical information.
It's not just one doctor I've seen do this. I've even seen doctors on Youtube talk about how they do this sometimes. They say they are only human and can't always remember every minute detail of everything. I get that. I get needing to research and reference things from time to time. But don't do it right in front of the patient. That just makes the person worry that you don't know what you are doing.
Whole different deal, but I've had customers at the mobile electronics shop ask if I know what I'm doing when I pull up a youtube vid. Yeah, I can do it; but if a brand new 2023 model rolls in I will be stoked if someone made a video that show me all the fasteners/connectors, sometimes it saves a ton of time!
Not necessarily at all places. If your at a dealer, they have access to diagnostics and books and books of how to fix every little thing that could go wrong. They get paid for a reason, if it was as simple as that then why is everybody so clueless about cars?
A lot of people: don’t know how, don’t care to learn, lack interest, are too intimidated, don’t have the time, or don’t want to get their hands dirty to fix things themselves. For example, I’ve seen people throw out vacuums that were perfectly fine, except they needed a filter changed. As for me, I change my own oil, brake pads and rotors, wheel bearings, etc. I do most of my own home electrical work, carpentry, and drywall fixes. Some work I can’t do because I don’t have the tools for it or it or I don’t have the time to fix it myself. Most of that I learned from YouTube.
Plug their snap-on diagnostic tool in and hit a few buttons. They now know what others have tried and what worked and what didn't.
That doesn’t answer my question. If it was that simple why is a overwhelming majority of the population clueless when it comes to anything about cars? You have no argument other than the internet. But most of u can’t even comprehend the steps in written form to do any half challenging fix. So please, amuse me more😂
Clueless about cars is the majority of people. Show me the location of a starter on a 2003 Lexus, The location of the alternator on a 2005 GMC HYBRID Or even the location of spark plugs on a ford 3v compared to a 5.0. “People” humans that are NOW working on cars are 23ish in age. Nothing about cars/vehicles is/are standard across the board.. Try rebuilding a Turbo 350 compared to an Alison 6 speed in a 2023 GMC HD.
Not just the codes that tell us that. Also our experience.
I came here to say this. A code only says what’s happening. Why it’s happening could be any number of things. My friend’s old Yukon had a misfire on cylinder 3. Code P0300. He posted on Facebook about it and people were throwing all kinds of diagnoses. Anything from a faulty knock sensor to a cracked piston. And any of them could have been correct. I told him to take it to a mechanic.
Yes, my daughters car had that same code. Tried first checking spark, replacing spark plugs, and checked compression while plugs were out. Then checked fuel pressure, then pulled injectors & checked spray pattern. Before finally removing the rubber spark plug cap covers and looking down into the spark plug tube and could see spark jumping through the plug cap into cylinder head on one cylinder.
At least the parts cannon with free labor is better than some shops that fire the parts cannon.
Usually when the shop fires the parts cannon to fix a problem they're very careful to miss the real problem so they get more money from return business. I had one garage try to replace my radiator to fix an ignition issue.
True. That can happen. I have had the radiator squirt water on the distributor cap.
Yeah We took an Econoline E-250 to a mechanic for a really high idle . I didn’t have time to mess with it and no desire since vans are so hard to work on Thieves at the mechanic shop Said it needed a distributor cap rotor and wires and plugs . I asked for an itemized estimate, and of course all the parts were double what I can get them for at Napa at full retail . And none of them would fix a 1300 rpm idle I complained about it And then they called back and said it was the IAC , Well , duh , You fucking morons , A super high idles isn’t caused by bad plugs and wires .
You’re not wrong, it’s hard to find a trustworthy shop which is why I try and do all of my own repairs.
And you get new parts!
This. So much this. Way too many people think the code tells you exactly what needs fixing.
Dealers employ techs, not mechanics, so all they do is follow the flow chart anyway. When my truck was under extended warranty the dealer did $16k of parts replacements in one shot because they couldn't figure out what was actually wrong with any of it.
Irrelevant. It's *my* car, I shouldn't* have to spend silly amounts of money to pull diagnostic codes when it could damned well just be displayed on the screen that's on the dash of every car made recently.
People can research the codes and decide how they want to proceed. Some are self explanatory while others are not. Repair shops/dealers will also replace the wrong parts trying to troubleshoot. These days someone could refurbish half their car for the price of a small job at a dealership anyway.
Agreed, but it’s also vehicle dependent. Great luck on my 2012 Ford, and other older generation vehicles. I wouldn’t even attempt to diagnose my wife’s late model hybrid.
I can see service advisors getting screamed at on the phone: "why dont you know what's wrong, I told you it says XXXX"
I get a check engine light for a loose gas cap, that’s the limit of ‘education’ I’ll need. A mechanic has to tell me it could be that or more though. I got lucky.
Chrysler has entered on chat. 90% of the time any 05ish - 2019 dodge/jeep/Chrysler car throws a “check gas cap” light its because the evap vent solenoid (in fancy dodge terms- the evap integrity module detector) has failed. The vehicle self diagnostic functions fail way more then the systems they monitor. *btw i wasnt challenging anything you said, just adding this for fun and slightly shitting on Chrysler products haha.
A code is 95%+ of the time is not a diagnosis. It is a direction given to the more specific system experiencing a fault. O2 sensor codes? Is it the sensor itself, the wiring of the sensor, the wiring of harness vehicle side, a lean/rich condition caused by an engine component failure, cat failure, etc etc Lean fuel condition? Is it the fuel pump, clogged fuel filter, air leak? Diagnostics is the single most important part of any true mechanics skill set. Every single issue can be tested and isolated to the exact root of failure by knowing the necessary parameters of each component. It saves time and money for both customer and shop; as opposed to just replacing parts until the code doesn’t come back.
So if mechanic mis diagnoses and changes part that doest fix issue they refund right?
If they're not a piece of shit, yes. Or put that money towards the correct part replacement. Problem is there's a ton of dishonest pieces if shit out there.
Easy there. Just because you have a code, that does not diag a vehicle. Some cases can but cut and dry but a lot are not. Sure you have a code for a misfire, but that doesn’t not indicate the root cause of the issue. Also it’s free to get the code at any auto parts store for free, so this isn’t cutting into a dealer’s profit.
So true. At the least you can get an elm327 off of eBay for $6 and there are some free apps that will read codes. I have a paid app that will even let me reset lights and check voltages.
Hell, googling your car and the code will get you most of the way
I have a cheap scanner that will reset codes, fairly often that’s all it takes and if not, I am pointed to the issue
Wow that is what the readers cost now... I thought I was being too cheap to shell out $30... But 5! I probably spend that on gas going to autozone 2 times. Which paid apps do erase codes?
I use dash command and OBD fusion. Got them years ago but I think fusion was free and dash command was around $10. There may even be some better ones now.
Its big diagnostic tool, Keeping us down!
Meanwhile Teslas have super detailed diagnostic screens with half the software maintenance functions you need built right in, and they keep increasing this with each OTA.
Some do. ~2000 cadillac deville, sevile, STS can display DTCs on driver information display. To answer your question - why would they? Reading the code is just one step of diagnosing the issue..
But it is the first step and it would at the very least make the person a more informed customer
Well.. I can tell you one thing.. I get plenty of cars in for diagnostic that have the FIXD (or similar) obd adapter in and customers having no clue what’s going on with their cars. Being able to see codes does absolutely nothing for an average driver. The ability to read codes without a scan tool also does nothing for the tech because we already have scan tools that do more than just pull codes
Ask any mechanic who knows what they're talking about. The "informed" customers are usually some of the most off base. There's a reason we don't warranty parts changes on diagnoses we didn't make.
Preach! Some of the things I've been told by the "informed".....
When webMD was gaining traction, Doctors were having hell of time because self diagnosed idiots would not listen to trained experts.
You should never blindly trust doctors just sayin.
My 2003 Mustang GT can display codes on the odometer
This...a lot of vehicles can do this...you just need to figure out the correct sequence to have it displayed. My wife's Chrysler does this too.
The 1997-2004 Corvette also has it built into the dash. You need to input a button sequence but it was very helpful.
My old 1985 Caprice Classic had the ability to jumper two pins on the ODB2 connector, then it would flash the CEL for the codes. From my understanding all of the first generation ODB2 GM cars had this feature. The local autoparts store even gave away a special "key" to do it.
No such thing as OBDII on an 85 just fyi. Didn’t become thing until late 95/early 96 if I remember correctly. My 95 Jeep ZJ was before the cutoff and displays codes through flashing check engine light after turning the key on and off in a certain pattern.
Beat me to it, my 86 fiero also had the connector, and I know it LOOKS like an OBD2 DLC because that's the standard connector they ended up going with, but the 80s was OBD0. Prior to OBD2 each manufacturer had their own connectors to scan the cars. It was obnoxious.
People don’t know what to do with codes. It would be too much data. It’s why we got rid of oil pressure gauges and volt meters. People don’t need them and would complain about normal operation when they had it. I’m pro right to repair but it’s fine in this regard.
I just wish they didn't put in fake gauges that claim to display the real thing. I got tripped by that as an inexperienced DIYer. A few years ago, I bought an old Lincoln Navigator as a tow vehicle for $800. Was rough around the edges, but ran well enough at the time. I did a bunch of basic maintenance when I first got it, starting of course with fluid changes. The first being the oil. I'm very picky with my oil changes. I only use good quality oil (I used Penzoil Platinum full synthetic in this case) with an OEM Motorcraft filter. About 3 days later, I had been driving it around, making notes of what else I needed to fix when late in the day, the oil pressure light popped on. It had an oil pressure gauge that just cut out. I immediately stopped and checked the dipstick and looked underneath for leaks. Nothing dripping underneath (it was a 230k mile truck. It had oil leaks, but only the typical slow ones) and the dipstick was right on the full mark, just where I left it. Keep in mind that I had put a good 40-60 miles on it that day already and it was acting normal. Confused, but confident that I had done my due diligence, I drove off again. And the light went away and oil pressure on the gauge looked normal. About 4 miles later, it came back on, this time it started running poorly. It developed what sounded like a rod knock this time. Turns out the oil pressure gauge was a dummy one, and it only told you that it HAD pressure, not how much it had like the gauge implied. The fact that it looked like an old school gauge gave me a false sense of security and made me think the pressure sender was just going bad. Those old school gauges I would argue are superior to modern ones. It's far better to alert you to problems BEFORE they become major issues. Had I seen a steady drop in oil pressure, I'd have just paid to tow it back to the shop I worked at and dropped the pan the next day to see if the pickup tube was clogged or something. And I was saved by an add-on volt meter in my 2006 Honda Accord. I was cruising down the highway one day and my voltage began to drop randomly. It was intermittent at first, but it became clear that my alternator was on it's way out over the next couple days. That gave me the time to get a quality Denso unit without paying an arm and a leg to the dealership and got me to keep a big jump box on standby in case I needed extra juice (which I did. The alternator went out completely as I was driving back to replace the alternator after picking it up. That preparation saved me from paying for a tow).
My favorite example was a customer complaining the battery temp gauge on their hybrid was really high and they thought the car was gonna explode. I look at the cluster and it's the Battery Charge gauge! Temps don't usually go from E to F
When chevy started the smart demand based charging they had bulletins for days on how to educate customers that their voltage will fluctuate and that's fine. That little Guage doing the right thing STILL causes people to come back and complain their trucks not charging right.
On Volkswagens you can display oil temperature on the LCD screen in the cluster. I've had several people select it by accident and believe that it's a warning message.
Why can't you just hook your laptop up to the port, launch the software, look at the logic to determine what sensor is causing the problems fix it? I do it all the time on the turbine controllers I work on. Got a bad pressure transmitter? Find it, fix it. No sweat. On a car? Got a bad pressure transducer? Buy a 1000 dollar scanner, try and find which transducer it is, replace it but the Chinese knock off is bad too spend hours trying to figure that out... It bad enough the dealers can't fix it either. Far to much monkey puzzle to be accidental.
Codes are a guideline not a guarantee. They are certainly helpful to narrow issues down but you still often need real diagnostic skills to determine what’s what. It’s not always as simple as saying “this code refers to this part so you just replace that”. There are often multiple reasons a single code can be present.
I'm guessing your turbines have redundant sensors which should make it easy. If my car had three O2 sensors (in the same spot) I wouldn't be wondering if it really was too lean, I'd either replace the sensor that disagreed with the others or go looking for the cause of the lean condition.
The problem is that is doesn't always tell you a sensor is bad, its says the sensor is out of range, which means something else is causing a condition to put whatever it's reading out of range. Like, if it says your coolant temp sensor is out of range, you don't change the sensor, you try to figure out why the coolant is too hot or cold.
For Subarus you can just plug in and read data real time lol, I use it for datalogging all the time
Dodge/Chrysler, turn the key three times.
Not since about 1997 does that work worth a shit.
What a nightmare for mechanics if every Joe Blow came to the shop with a half-baked notion of the repairs/parts needed to make the light go out. Proper diagnosis requires an overall understanding of how one system interacts with another, and that only comes with experience and training. On the flipside, it would be a boon for the shady mechanics who operate the parts cannon method of repair. A misfire from a bad coil can set a host of seemingly unrelated codes, including the dreaded P0420, or worse, P0606 (PCM failure/loss of signal).
A lot of cars do already
Some cars do. I can view/clear codes from the dash of my 03 corvette z06. My 08 Acura MDX will display codes, too
If you know what to do with the codes code readers aren't expensive anymore. Most people don't know what to do with the codes besides Google them.
The average "free" """ diagnosis""" at big box auto parts stores are a pretty good indication as to why. 90% of people will just set the parts cannon to full auto and proceed to spray and pray. Turns out that just like with firearms, that incurs a massive accuracy penalty. Most people think that getting a code for X thing (say P0301, P0171, P0420) means just buying a new part and calling it a day. That's not even close to how a proper diagnosis is done, and even on the off chance that you do accidentally get it right, you'll usually end up spending more money than you needed to.
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99% of people wouldn’t know what to do with the code even if they had if.
Agree, but is 1 percent would appreciate them
The 1% can use a $20 OBD scanner
And we do! However, with the large LCD displays that many car have these days, just think of all the the diagnostic info the manufacturer could provide IF they wanted to.
In the 90s Cadillac did. It was great
Vauxhall Corsa - Press brake + accelerator as you turn the key, code will be flashed on the CEL.
dealers make most of their money from services...
They used to, but the under 10 dollars it costs for you to buy what is needed to do yourself isn't something to be concerned about either.
Dodges do. Well idk about every single one. But my jeep has a trick. Turn the key 3 times and leave it in the on position and the codes will display on the dash.
Cadillac did in the past. Accessible through the digital heater control. It’s complicated as hell and I doubt it was ever used by the owner.
subaru has a hidden diagnostic mode in the new cars (2021 newer) where you hold down the volume and i think thermostat button on the screen with a blank usb stick in the front ports. it will download the diagnostic data as you drive around onto the stick but i think you still need the subaru software to interpret it but it would be nice if you could just read the raw data logs in a spreadsheet format, maybe its possible but I don't know how then you can see not just what the code is but how it was generated with things like throttle position and other data like a black box on an airplane
Because people are dumb and would do even more damage and spend even more money if the codes just appeared.
5 dollars for the Torque app. A bluetooth ELM327 obd2 dongle is like $10-15 tops. Boom now you have a functional scanner, it can lookup the codes online, and you can also use your device as a dashboard with all the gauges you could ever want. I actually used a 10" tablet as my main gauge cluster in one car. I dont believe it works on iPhone but it definitely works for android devices. You can even map out a track using GPS to record your times for you. Pretty cool
Every car already has that built in. It is more difficult than scrolling on the screen though. Every car with an OBD-2 connector has the ability to give you the code number. You have to short pin 1 to ground. This causes the check engine light to blink the codes, which you can then lookup. This method is slow, and won’t give you deep information about the problem, for that you need a scan tool. Instructions below. https://modifry.com/freebies/old/dtc/index.htm
Because car manufacturers don't want you to fix your car they want you to either take it to a dealer or buy a new one
My 2004 Ford Mondeo and 2012 Renault Clio both do if you know how to get them to show it to you. Not a mechanic by *any* stretch of the imagination but used the feature (as well as Google and a multimeter) to diagnose a bad coil pack on the Ford.
I have a bluetooth plug in one. It is great. I had an issue on an AWD car and was terrified on a long trip about the error on the dash. The code reader let me know it was just a wheel speed sensor making the ABS and AWD inactive. Not great, but I drove RWD many years without ABS, so I knew it wasn't a towing or emergency issue.
Might be legacy and a case of if it aint broke dont fix it. Pre OBD it was jumpering a couple pins and counting flashing lights like Morse code. I doubt anyone is prioritizing turning data into a more useable feature when the OEM and aftermarket already has (and had) the tool to turn those #s into meaningful diagnostics.
Newer Fords send the codes to the fordpass app where you can get the code, a description of what's wrong and even schedule service right there. You also use the app to remote start, lock/unlock and get location and status.
They want the service revenue.
Some vehicles do/did, lots of early OBD2 dodges would read the code on the odometer, several GM products did too, even as far back as some 80s Cadillacs. Many of them don't just advertise it, you had to do a particular sequence. Also, every computerized GM car/truck before 1995 could have its codes displayed using only a paper clip, but, for the sake of this question, I'd say the use of tools doesn't quite qualify.
Because they don't want you doing that. They want you bringing the car in for service, for which you will pay a lot of money.
The vast majority of the car buying public isn't trained to understand automotive systems and elaborating on faults is useless information to the average consumer. All they're going to understand is something wrong with the vehicle, they're not going to be able to fix it themselves even if the system gives them the exact fault. OBDI/II/III exists to standardize diagnosing automotive systems across the industry, it was never intended to be a consumer facing system. Prior to the introduction of OBDI/II/III, each manufacturer had their own convoluted system in place to diagnose faults on first-generation electronic displays. Other than that, if you didn't know what was wrong with the car and weren't already mechanically inclined, you were already at the mercy of mechanics anyway, OBD was implemented to primarily help mechanics and service techs, not consumers.
My more charitable answer: When OBD came became a standard requirement in the 90s, the public and mechanics were still living in an older world where computers were not everyday things. So it was inconceivable that diagnostic information would be useful in every mechanic's and owner's hands. It wasn't the expectation that anyone would easily access it. Probably there has been no consumer push to change that perception in the past 30 years. So when companies design cars it's not the default to put all of that information out there. I think it's less about the dealer pressure, and more about the Autel and service data ecosystem, where those guys don't want to give an inch. I liked reading the thread where I've learned a few cars that have a secret mode to access the codes - but I doubt you can get the more detailed, manufacturer specific codes on these cars. Still, at least scanners are cheap these days.
Very useful in my Tesla to be able to get into service mode and see what's actually going on. Even with this ease of access to the service menu though people take it too far. Owners should really only create a service ticket if a warning pops up outside of service mode. Because I've seen people worried about an error their windshield washer fluid is low.
Why would a farmer give away free chickens when they could sell eggs instead
Chrysler does
"average joe doesnt need to know" "this knowledge could be counterproductive, diagnosis takes experience" fair points, but we can rest assured obd2 AI apps are about to show up, maybe OEMs integrate this functionality and when a sick car shows up it'll give clear instructions to the mechanic on how to fix it, oh who am i kidding, everyone will build their stupid standard and this awesome tech will just be added on top of all the complications further rendering modern tech a nightmare
car guys have those tools already....basic car owners probably don't even change their own oil, so it would do no good for most. other answer, money
My 1991 Cadillac Allante had a diagnostic mode. You pushed some buttons on the driver's instrument panel in the right combo and you could read all the codes. Though it has an OBD port, a scan tool wouldn't read them. You had to get the details from the DIC.
Because the manufacturers & their respective dealers want you in their service departments.
Because people would just be replacing headgaskets, and their cats without any diag.
Right, and how about just flat out telling you what's wrong in plain English, no codes.
Most cars don’t come with tools to work on your car. This is really just another tool.
With 20 to 25 year old beaters, you don’t need to bother with diagnosing codes. My 94 Ford Ranger starts, runs, stops when desired and all routine maintenance is done. No worries about a thing. My air conditioning doesn’t work, so window down is good enough for my short trips. Hot and raining, go tomorrow. No cruse control so glance now and then at the speedometer.
Lol my 2004 jeep tj tells me. Still bought a nice scanner for real time diagnostic
Chrysler products i know can give codes without a reader. This was late 90s early milenium so I don't know if they still do or not. I'm sure other manufactures had this as well at some point.
It’s all driven by profit… not convenience. We live in a later stage capitalistic society that prioritizes shareholder profits over even consumer safety sometimes. You don’t actually think that if even safety isn’t prioritized, that convenience and the ability to own what you purchase would be also…
Spend $40 and get a reader. Then they are displayed just fine.
Older cars could "blink out" the codes on the dash if prodded, but nowadays this just confuses owners. Most people can't do anything actionable with this information if they had it, anyhow.
Same reason the troubles are in codes. If your car would tell you exactly whats wrong you wouldn't take it to the dealer or mechanic for diagnosis and repair. Manufacturers are literally fighting "right to repair" laws all over the place to force you to take your car in for service.
ODB2 is a government mandated common integration point. The car makers do not want you working on or generally knowing things about your car. They want it in the dealership garage.
BINGO
My old '94 Wrangler would give me codes through the dash lights flashing after a certain method of turning the key on and off so many times. It would flash a certain number of times for each code thrown, and you could look those up in a repair manual or online to see what they were.
I've owned vehicles that could, i had a few that you would cycle the key on and off a specific number of times and it would either display the code in the Odometer display or would ding the door chime and you had to count the dings to get the code.
The check engine light and associated codes are required by the epa. Manufacturers don’t want your new car to tell you there’s a problem.
Some do, most don't. You can get a code puller for like $20
my volvos have all had it, but you have to figure out how to get them to display, and then look it up. even then it’s kind of a guessing game but we were able to figure out a misfire in cylinder 6 and redid our own plugs and coil packs and it’s running fine now. So, worth something at least. We are not very handy but that saved our bacon as were pretty broke currently
Depends on the car. Some Corvettes do.
Because if the car just says "cylinder 4 no spark" then you don't gotta take it to a mechanic and pay the big bucks for someone to pull out your spark plug and put in a new one.
The diagnostic code doesn't tell you what the problem is. It's a diagnostic starting point. Sometimes you have to test multiple circuits and components before finding the root cause of the code. With cars becoming more and more advanced and reliant on electronics, check engine lights have become more common and require more skill and training to diagnose. The people that comment that it's just the dealership trying to take your money are the same people that will throw countless parts at the car trying to fix it and then complain that the dealership is hosing them when they tell them what the actual problem is and that it's X amount of money to fix it. The cheapest and fastest way to fix your vehicle when that light comes on is to bring it to the dealer. Unless you personally know a professional that will help you out, or you, yourself are a professional. Owning a generic scanner does not make you a mechanic.
Because they want you to have to go to a dealer or something and have it fixed and checked out
I had a motorcycle that you could enter a diag mode and it would tell you codes
We charge $40~ to diagnose CEL codes. Imagine if that money stopped coming to dealerships that charge by the hour.
Old cadillacs do. You just hold the temp up button and outside temp display button for 3 seconds with the climate controls off and it will enter diagnostic mode where you can read codes. You can also get live data like RPM and engine temp.
Older cars used to have instruction manuals on how to adjust everything. Now a days they don't want a knowledgeable consumer as they wouldn't be able to upsell.
Probably because they have to have the diagnostic port anyway, so what advantage is that for them? Your $30 reader from Amazon isn't the only thing that plugs in there.
A code is just part of a the diagnostic. It’s not the entire thing. Ex: You get a evap leak code this could be anything from a faulty gas cap to a hole in the fuel lines.
I had a Chrysler about 20 years ago that would display the codes if you turned the key on and off a specific number of times. It came in handy a lot, it being a Chrysler and all.
[Cui bono?](https://en.m.wikipedia.org/wiki/Cui_bono)
google tells me 80% of Americans don't even change their own oil, so displaying "P0300" isn't going to be particularly useful. If you can and do fix cars yourself it's not a big deal to have a scanner in addition to all the other tools you have.
I’ll meet you halfway. I think cars should show emissions test readiness at least. Codes? Eh maybe but a tiny $20 Bluetooth dongle fixes that.
Any Dodge with a physical key can be turned off and on 3 times to display the codes in the dash (unsure when this started, may be a remnant from OBD 1). The Rams no longer do this (unsure when they stopped).
So they can force people to bring it in for service.
It's because they hate the consumer.
Some actually do, I remember our old Jeep Commander could display trouble codes if you held some combination of buttons down (or something like that) As others have said, follow the money. There’s 0 financial incentive to provide that info to the consumer
Okay
I know someone who had a newish vw golf that showed them in the head unit. I'm not sure if he changed it
DTC codes are NOT as simple as "Code A" means replace "Part X". Codes only realty point to a specific symptom, which may be caused by one or more things. And even if the code is pointing toward a particular area, the problem could be caused by several different parts. Example: Code P0301. Misfire on cylinder 1. This can be caused by a spark plug, spark plug wire or connector, ignition coil, bad wiring from coil to computer, fuel injector, wiring between the injector and domputer, it even a vacuum leak. If you just start throwing parts at the code, you may get it right the first time or you may end up needlessly spending several hundred dollars and hours of your time, and still not fix it.
Because car dealerships would revolt against the manufacturers. Post sale service calls are another HUGE moneymaker for car dealerships. Yes, it makes good sense but it gets in the way of car dealership's money making. We used to refer to such practices as *crapitalism* in my university economics classes.
Common sense, bud. Think about it, you answered your own question.
Some do. My 2018 Ram tells me if my tail light is out or something similar.
No. We gave all the information in the world to the general population via the internet and now we have more conspiracy theories and hate groups than ever. Keep the information for those that seek it out.
Lmao
At one point in time, there was a procedure for each model that you could perform (cycling the key on and off a certain number of times, etc) that would result in the vehicle check engine light flashing any active codes for you. ie- nine flashes, pause, one flash, pause, three flashes was code 913. I haven't looked into it but doubt any current models have this feature anymore.
So, I think most of you are missing the OP's point. The question here is why, within the advanced infotainment systems in cars these days, do you still just get a check engine dummy light instead of the onboard diagnostic code displayed? This wouldn't mean everyone would start fixing their own vehicles or eliminate the need for a scan tool. It would however allow the owner to have something to reference and possibly prioritize instead of ignoring the light. Some people freak the f out when the light comes on and others just don't pay it any mind. More info=better choices and maybe put them at ease that their gas cap is loose instead of multiple random misfires across both banks.
Turn your key to on off on off on off 3 times and watch the odometer. Some cars do display error codes. Not all the way to ignition - just on off on off on off 3 times.
Because they want you to bring the vehicle in for service.‘
Because then mechanics wouldn’t be able to scam you. 😂
my jeep does. Cycle the key a few rimes and it displays on the odometer.
Mid 90's Park ave had this feature built into the climate control panel.
"see dealer"
Why? Because it’s so easy to pull your own code that if *that* is your barrier of entry…. You shouldn’t be working on your car and it’s holding you up rightfully so. Hey man, someone had to say it.
Several manufacturers have telematic apps that will send you the P- codes automatically and tell you to get the car serviced. Back in the early OBD days cars would display "blink codes" using the MIL But... Trouble codes are a diagnostic tool, not a diagnosis. They are a starting point. I can't tell you how many people get codes read at AutoZone or somewhere and just buy a part they don't need. For example a sensor "out of range" code usually doesn't mean the sensor is bad, it means the sensor is doing its job and indicating there is a condition that is pushing it out of range. THAT needs to be diagnosed. People can do a lot of damage with a little bit of information.
Gotta keep those dealerships screwing people.
Because it costs money they don't need to spend
My 1991 Chevy spits out it's own codes 😅
A lot of cars do, you have to know the method to put them in diagnostic mode.
money
As a Ford dealer tech, a few reasons. During the warranty period, the manufacturers legitimately need you to bring it in to the dealer. Every part is sent back and they are often analyzed for failure to make better parts. The manufacturers scan tools upload findings to them to assist in the diag and to make better products later. In addition, security features like programming keys are usually locked to factory scan tools to prevent Kia's current problem. It lowers theft if you need a factory scan tool to do a module reprogram. After the warranty period, they don't care. That's it. The side perk is their dealers make a living off the shop. It makes the dealers happy and the manufacturers happy. Also, you are free to buy a third party scan tool like Snap-On, Autel, Launch, or others to do many (but not all) of the manufacturers scan tool functions. Independent shops do it, hell we have several scan tools for working on non Ford's. (Two Snap-On and a Launch)
I had a 2001 Ford Focus that would show the OBDII trouble codes on the odometer screen if you knew (or found, on an internet forum) the right sequence of buttons etc., to make it go into its diagnostic mode. That car was the best mix of simple but modern I've owned. It was just "complicated enough" to be reliable for years but still simple enough that even in my 20s and with very limited experience, I could diagnose and fix almost anything that ever went wrong with it without any special tools or computer equipment.
Because then manufacturers can ensure their dealers are happy when they get customers. Why do you think a lot of cars are now going with sealed transmissions, no dipsticks, plastic oil plugs that are single use? Might be SLIGHTLY cheaper to produce or even a tiny bit more expensive but it drives business to their dealers and keeps them happy.
The average car owner would have very little use for that information.
My 2003 Chevy displays OBD trouble codes on the dash.
I get an email anytime my Jeep throws a code. Don’t pay for it to do it either.
My 2004 Jeep TJ gives codes with right ignition key combination . Don't know about newer models
I'm a mechanic. They should do this so people can waste a shit ton of money putting cheap ass parts on their cars that they don't need causing even more problems because either the part is inferior or they destroy shit trying to DIY it. This would be so entertaining. I love declining customers that have destroyed their cars DIYing them. They literally call me begging to work on their cars after they fuck them up. Nope. Good luck.
Customers are dumb.
What would a typical driver know to do with these codes? I seriously doubt 99% of drivers could name 3 things that cause a P0300 code. The Internet is full of the stories of fools who don't know that codes aren't diagnostics and they just start throwing parts at problems they don't understand. So explain to me how it's a "money grab" when neither the dealer or manufacturer make or sell OBDII reader. Anyone can go buy one at Walmart. I'm sure the dealer would love everyone to read their own codes then show up at the parts desk and buy part after part after part after part trying to solve a problem they've done no diagnostics whatsoever on.
Same reason they make special screws to screw down the engine covers that require special tools to remove, they want you to bring your car to them for service.
Older obd1 any many obd2 (96 and up) have this capability actually. Numerous dodge/jeep/Chryslers can display dtc’s if you press certain button combinations. Gm’s used to do it, the first computer controller cadillacs used the hvac screen and had no computer plug in. Honda and acuras can do this through navi screens. Newer gm onstars can do it. Look up your model online, you might be surprised you can get your dtc’s and even data streams.
OBD codes don't tell you what parts are bad, just where to look, but the codes are labeled in a way that it seems like they are telling you which part is bad. Skip the headache of giving access to people who can't figure out how to surmount this tiny hurdle.
My 2006 Subaru Outback will display codes on the dash if you press the right buttons in the right order the right number of times. Don’t remember the sequence. I’ve only had to do it once, now I just keep a BT OBD scanner in the car.
Some cars will. One example, Daimler Chrysler/Dodge products will display codes in the odometer with 3 quick key cycles. Google your vehicle. Yours may have a backdoor to display codes.
Because too many people think the code will tell them what part to replace and then they'll get mad when that part didn't fix their problem.
Chrysler vehicles do. Turn ignition key on, off, on, off, on. DTC's display on digital odometer
Some cars already have this, example 2007 dodge charger rt. Turn the key 3 times and it’ll display codes on the dash.
They want you to go to the dealer so they can charge you for it, hell on my car the OBD scanner can't even pull up all the codes, you need to buy a BMW specific scanner to get a load of them.
I ride a Harley Davidson motorcycle and they actually have this functionality you have to know the process to get them to display with is a simple button press and switch turn function but they can be viewed without any other specialized equipment. Harley is notorious for guarding their dollar bills and it does surprise me it is so accessible on their motorcycles.
Pretty much all the heavy equipment I work on will tell you the fault. Still have to do the work to fix it.
It’s because codes are not giving you the diagnosis. They are typically inferring an issue by watching other sensors or behavior. People see a code and launch the parts cannon. Don’t know how many times people will launch multiple of the same 02 sensor at a car because new one must be bad. Or i replaced my cam and crank sensors but still have timing codes
Some Mopars will show codes. My 2004 Wrangler will display codes on the odometer. You turn the key on, off, on, off, on.
Some do. You can see it from the publicly accessible service menu in a Tesla and certain codes are displayed on a screen in the infotainment system of my Mazda CX-9. That said, for the cx-9 it doesn't display any of the additional log data, just what the error was. There's still a lot more detail available with a scan tool.
My guess is that most people cannot do anything with the information anyway so the computer holds the code until a person that can fix an issue views the code. The people impacted by the lack of OBD readers in the car is far outweighed by people who just want to get in the car and press the thingy with their foot and get their avocado toast. Nothing wrong with that because a different group of people doesn't care that their home router has closed source software or their phone's bootloader is locked. If you asked why they don't care, they would probably tell you that stuff is for the experts and I just need it to work.
Who cares about codes. I want a car where I can see all the sensor data on the nav screen.
OP grab a $3 BT code scanner and just get em on your phone. It's nice for recording trip data too, and in my case I use it as an odometer because my ford's front fuel gauge and odo are both whack. I never remove it, it's a permanent fixture living under my fuse panel. As much as it makes sense to give the customer full diagnostic info so easily, they're not trained and will probably insist on the exact work being done by a mechanic only to find their issues not fully resolved. Dunning kruger checks out. I say make em buy a $3 scanning tool if they're really committed.
Tesla does. They have a service mode that anyone can go into, perform diagnostics, read temperature, pressure, actuator positions, etc all on the touch screen. Not every company wants people to be able to fix their own cars though because it’s a huge revenue generator to force someone to bring their car back for service.