When I first started in this glorious, noble profession of automotive journalism, I was young and innocent and full of dreams. Big dreams. Dreams of the future bringing wonderful things, like cars universally equipped to display, right there on the dashboard, without any need for plug-in readers or trips to a mechanic, any On Board Diagnostic (OBD) codes that the car may have, along with normal-language descriptions of such codes. These are the codes that cause the dreaded “check engine” light (CEL) to appear. I wrote about this dream way back in 2011, and now, nearly a decade and a half later, there has been effectively zero progress on this front, and I think it’s as important as ever.
I know a large portion of our readers will just think “why is this a big deal? OBD readers are only $20! And they’re stylish!” and sure, moneybags, OBD readers aren’t that expensive, but that’s not really the point. Yes, we’re people who think about cars most of their waking hours and have no issues rolling on the floormats of a car and feeling around under the dash for that chunky OBDII connector, but the vast majority of people who just use their cars as transportation appliances are not comfortable with such things, and in many cases, aren’t even aware there is a port under the dashboard that, when you plug a little doohicky into it, will tell you why that check engine light came on.
The truth is that most people are in positions of terrible knowledge imbalance when it comes to repairing and maintaining their cars. They’re at the mercy of whatever the technician or mechanic says, and while I’d like to believe in the fundamental honesty of humanity, we know that’s sadly not a guarantee. People get taken advantage of all the time, and part of the issue has to do with the relative difficulty of getting diagnostic information about their own cars.
What makes this especially galling is that this denial of information to car owners is completely preventable, and would be trivially easy to do on pretty much any car that had been built in the past decade or so. Once, sure, there were issues with figuring out how to get information like specific codes because cars had very limited alphanumeric display capabilities. Though, even then, carmakers (very) occasionally would come up with clever, convoluted solutions to do this, like on this 1995 Cadillac Seville:
A few other cars had similar sorts of systems:
That was a long time ago, of course. Now, modern cars almost always have a full-color dot-matrix LCD screen that is not just capable of displaying CEL code numbers, but entire blocks of text, and hell, if you wanted, diagrams and illustrations or whatever. There is really nothing stopping all carmakers from showing a code that caused a check engine light, as well as a full description of what it means.
Just picture something like this that could appear on the center stack screen of a car when a check engine light code is thrown:
Why not do this? As it stands now, cars throw a check engine light, and for many people, that just means they look at it nervously as they fret about how much freaking money they’re going to have to dump out for whatever the hell that light means. Why should people be kept in ignorance about the state of their cars? Every car owner has the right to as much information as their car is able to give them. All cars know the codes they throw; why do they keep it a secret from their owners? Not having an OBD reader or the comfort to use one or the resources (time, money, opportunity, whatever) to go to a mechanic is simply not a good enough reason to keep the car owner ignorant of what’s happening under their own hoods.
If cars would just display what the code is and some manner of description on their dashboard screens, easily accessible to the owner, then at least the owner would have some sense of what they were dealing with. A CEL can come on from anything from a loose gas cap to a severe failure condition of some kind; any information about what’s going on is good information, isn’t it?
Plus, trouble codes could be saved to a car’s internal log, and, since so many cars have internet connectivity of some kind already anyway, why not give an option to send those logs, complete with timestamps and all relevant information, to an owner’s email, so they can then send it to mechanics or car-savvy friends to get an estimate or an initial diagnosis?
I get genuinely worked up when I think about this, even after all these years, because I’ve talked to too many people who feel helpless when it comes to getting their cars worked on, and the issue almost always comes down to a lack of reliable information. I’ve bought OBD readers for several friends and showed them how to use them, but I shouldn’t have to do that.
I’d actually like to see this become legally mandated. That’s right, I said it, I want to involve the authorities. When I’m Emperor of America, all cars will be required, under penalty of having the CEO of the offending carmaker placed in a dungeon, to display as much information as the car’s owner wants for every failure code that gets thrown. That includes standardized OBD codes as well as manufacturer-specific codes. If you own the car, this is, by right, your information. If carmakers can be so cavalier about gathering information about us – and they definitely are – then they can at least give us some actually useful information back.
These codes, along with detailed descriptions of what they mean, can all be downloaded to a flash drive or emailed to a specified address, so the car’s owner can do whatever they want with that information.
It’s absurd that this is not how things currently work. All new cars know their codes, all have the means to display them easily, and yet hardly any do. I’m not sure how to convince this industry that this matters, but I feel like it does. This is similar to the right-to-repair laws we’ve discussed before. This is an easy fix; just a bit of interface design and some software coding. Ideally, the way one accesses this data should be standardized across cars, too, so everyone knows how to find the information.
We have a right to know what our cars are telling us, without intermediaries or other equipment. We’ve been in a position to do this for well over a decade, and it’s time to actually make it happen. Carmakers, let people see what their check engine lights mean, right inside their cars. It’s time.
Torch this would be great. However please inform me how the exact description of what is wrong when even when I go to the parts store to get a reading, yes any person can drive to the parts store and have an employee scan the vehicle with the most modern equipment, and then you get a readout of anything from a little problem to horrific problems. How can manufacturers provide exact information when even mechanics and auto parts stores can’t actually give you a correct answer?
At one time I owned a Dodge Caravan. I think it was a ’91. Not quite a stripper model, it had air conditioning. But I had to purchase and install an aftermarket cruise control myself.
That car had one feature unlike anything I’ve had before or since: Turn the ignition ON-OFF-ON-OFF-ON – within the space of five seconds, and leave it in the ON position and count the blinks. It would rattle off the stored codes, which you could then translate from several readily available resources – the internet wasn’t as much of a thing then – and you could sort them out on your own.
Now, with two completely different digital screens in my car, I am getting less information from the vehicle’s self-diagnostic systems. How is this progress?
My other vehicle has no computers in it unless I physically set one in the passenger seat. That one, the Check Engine Light is a flashlight.
My OBD1 Subaru had a pair of connectors under the dash that you would connect to get a morse code-like flash on the dash. Key cycle is a better idea.
I had a ’94 Dakota Sport that did the same thing.
Your door is a jar
Your mind is mutton
You want NEED subscription services
“How can a door be a jar?” …
“Why would they put a jar on a car?” …
“Oh man, the freeway’s melting!” …
“Put it in the jar.”
As a IT person/SW developer, I have learned that information multiplies what the user is: Info * Stupid or Info * Intelligent. So I understand why manufacturers sets the Info variable to zero. I really do.
OTOH getting OEM servcice data / manuals is stupid expensive, and third party info is less than perfect.
I think Microsoft is mostly right, making the information available if you know where to look, but only show the easy version to ‘the masses’.
“Microsoft is right about interface design and information shared with the user” is a nice 2025 take.
The Linux community is happy to take the Windows 11/Copilot refugees, though “Automotive Grade Linux” is unfortunately incapable of solving the car problem.
You misread that. I was not writing about the Windows end user experience(*). I was writing about how Windows, its API and components (fex AD) are documented and readily available for free.
(*) Tip: Server editions are much nicer and cleaner as clients, than the last few client editions.
Ah, I see; you basically meant the opposite of how I read it. In favor of available information, not restricted information. Thank you for your patience.
I’m (as established) Linux-using, so I object somewhat to harder separation between “user” and “developer”.
Users should have the opportunity to become developers, rather than being actively or passively barred from learning outside of establishment channels.
I also believe encouraging curiosity/understanding in general makes users safer from both malicious behavior (by vendors and third parties) and their own error.
I concede in the latter case, it could be harmful to follow a design philosophy that otherwise discourages understanding and to then suddenly provide information; but I consider that a consequence of hiding information from users, rather than a justification.
(Jason’s suggestion of including an explanation of the codes would address this in the context of the original suggestion.)
Never tried alternate editions of Windows, though I imagine the server edition is closer to how I configured Windows than the “fresh” install, with all the ads and hard-to-remove cloud integrations.
I think Microsoft was right… 15 year ago. Like, with windows XP/7.
Current microsoft offerings are ad-riddled nightmares that obscure data almost as badly as Apple does.
Sigh, gonna have to install linux on my boxes now…
I always thought an OBD2 reader would be one of my first purchases after buying my first car, but then I had to go out and buy a pre-OBD2 car, and so I still don’t own a reader!
As an aside, the OBD2 standard is almost 30 year old. Isn’t it past time for an OBD3 standard?
No. Look up the ideas for it.
Maybe the car could send the information to your CEL phone. (SCNR.)
Hell yeah I’d vote for this. If they can put the f$@king glovebox release in the screen they can display the damn OBD codes!!!!
On a related note, I’m irritated that manufacturers still don’t include a built in Fuel Shark. I hate having to remember to plug it back in after I charge my Garmin.
You could get one of the OBD2 versions, but then how would you check codes?
Torchinsky would like to have a word with you about your Fuel Shark.
I also fully agree. Take it one step further though, and delete the engine, so there is no need for the check engine light…
Hear, hear!
The trucks I work on at work (a certain brand that used to make pickup trucks and farm equipment) you can see some of the codes on the dash but there are a lot of codes you need to use a service tool and softwate to see them. Albeit I am in R&D so it makes sense some of the codes only show up on service tools. This is much better then my Polestar which I need a special tool and software to even read anything from it just ridiculous as normal OBD scanners do not work on modern Volvo’s. But I agree we should be able to go into a service menu to see any active or recently active faults without needing a scanner or laptop with special software.
Ooh, Polestar? I’m currently considering a used P2, anything you’d recommend I look out for?
From my knowledge there isn’t much to look out for besides not getting a 2021 since it will not have the heat pump (if you live somewhere cold that is) besides that there can be some sensor issues depending on which packs the car has. Mine will throw random BLIS errors once and a while but it normally clears itself if the car is shut off for a little bit I am assuming software issue or possible a bad sensor. Some forums and videos I have seen have had some suspension issues mine is a little squeaky in the back but nothing terrible. Besides small things like they above I haven’t had any issues with my which has all packs and I have had it for about 6 months now and got it CPO through polestar which his nice because it adds a 2 year unlimited mile warranty on it even if the original bumper to bumper is up.
‘Sup Harvey
Hola Senior Harvey
Thanks! There’s a ’22 with all 3 packs near me that I might go look at. These things have come down to a price that makes them hard to ignore.
Yeah that is exactly why I picked one up I got my 22 PPP + it already has the performance boost on it with 50k miles for like 26.8k was really hard to pass it up they have actually increased their prices a little bit through polestar since they were selling like hot cakes at sub 30k prices with the CPO
Tesla’s service mode is a great model and should be copied industry wide. It’s just hidden enough to keep people who are randomly pressing buttons out, but it lets anyone with a modicum of experience (or google) see everything that’s working or not and troubleshoot.
I had a rental Model 3 that would not engage cruise control. Service mode showed me which component was the trouble and then gave me a button to reboot the ADAS computer. Five minutes in a parking spot and it was fixed.
These codes are exactly the level of effort hidden, i.e. minimal, to keep Jerry and Karen from thinking that they know what’s going on. No one who shouldn’t be kept away from these codes is unaware that you can just read them by visiting your local Autozone and spending zero dollars
I don’t know about that. I found out what a P0303 (If I remember correctly) code meant after the fact. If I had known that ignition coil #3 had pooped the bed while on the side of the highway I would have had options besides tow to a shop and pay far too much for tow and replacement. My name is neither Jerry or Karen by the way.
I know better now but when this happened the first time it would have been nice if an “ignition coil #3 failure” had popped up.
I remember once showing a grandma who had come in to the parts store I worked at how to get the flash codes to display in her 90’s Caravan by cycling the key three times. She was overwhelmingly happy to get this tidbit of info and simultaneously pissed at the manufacturer and dealer for not giving her this info.
Thank you for confirming my fuzzy memory of getting CEL codes for my 1990 Dodge by counting the # of times a light flashed on the dash after performing some sort of key/button sequence.
You mean like the BMW owner I know who keeps an OBD reader plugged in at all times so they can see what the daily random fault code actually means? Agree. The car knows what’s wrong just tell me!
My 91 Riviera has an on board diagnostic mode, but it’s so cryptic it’s almost as much work as blowing the dust off of my Tech 1. It would be a fantastic idea to have such a system on new cars, especially since they’re so integrated with technology that they’re one step away from having pop-up ads.
They won’t do this, but they WILL provide a way for the car to tell you how much oil it thinks it has – for the low, low price of taking your dipstick away. We also all have to pay for TPMS now, but only the very generous OEMs will use it to show you actual pressures instead of just a “low” notification.
the fact that all cars won’t tell you the pressure for each wheel is bonkers.
Not all cars know the pressure for each tire. Some TPMS use the wheel sensors to determine when a tire is low relative to the others, it’s all based on wheel speed per corner.
Some tpms systems use rotation speed for each wheel then determine a tire is low on air if it’s rotating at a different speed. My car apparently does this so there’s no way to get psi data.
but I’m saying we have the technology. it’s (almost) like the one-touch up/down power windows. We clearly have the technology for each window to be like this. but some cars are still farting around with driver side only or only one-touch down or one-touch up. make it consistent.
I hear you there, even on cars where it has a true tpms it’s really aggravating seeing the light go off and then you have to figure out what tire it is lol. Maybe that’s on purpose to get the owner to check tire pressure on all of them? Also it’s nice seeing the psi readout when it gets cold so I know to attribute just one psi under spec to morning weather that will be fine in the afternoon.
exactly. some in my fleet have exact PSI. one says which tire is low (but not how much) and one just says there’s a low tire and you figure out which and by how much. Not a big deal by any stretch, but it still irks me from a “WE HAVE THE TECHNOLOGY!” standpoint.
My 22 Silverado shows actual pressures for each tire. Except the spare, which means it whines at you when driving on the spare.
I’m not opposed to this, but it wouldn’t be my first priority if I was emperor of America.
PSA: Most part stores will read your code for free and give you a page with the likely cause. In my case it was wrong but that’s about as good as you can get trying to diagnose based on codes alone.
lol, I worked with a data science team that developed one of those proprietary code readers – initially they used the scanned code along with the parts purchased (after removing any returned parts) to identify the most likely cause.
Their initial presentation to us showed the #4 most likely fix for a code on a Corolla to be a Snickers bar.
That’s awesome. I can see it now, some slide deck showing what trouble codes are fixed with Slim Jims, Gatorade, M&Ms, and whatever other impulse buys are at the parts counter.
Brawndo. It’s what cars crave.
Yeah, I think I still have a screenshot of the slide somewhere – I do recall one of the other most likely fixes was wiper blades
Obviously, mandating the use of amber turn signals would be first.
On my Fiesta I have a Bluetooth OBD2 adapter plugged in full time and I run ForScanLite on my Android phone. Way too much info, no way do I want that stuff popping up in my face on the dash when I’m wearing my normie suit.
When I look at some of the stuff it makes realize even my superhero suit is getting a little threadbare.
It is obvious that SOMETHING is stopping mfr’s from including OEM code readers in their giant screens: Dealers and their “repair” shops.
One thing people can do is stop buying cars without this feature. And reviewers on this site should note the absence in their reviews.
I recently bought a reader, because my car will occasionally “misfire” when starting up (not enough gas to the engine, as it is parked slightly uphill), but it is clearly OK afterward. So, I plug it in and clear the code.
Apparently, from a poster, Honda/Acura cars show the code and/or issue. So, for me next car will be a Honda/Acura.
Maybe one of those aftermarket dashboards that Mercedes wrote about the other day will include them.
So we can only buy vehicles from one manufacturer. That’s helpful.
This is a car enthusiast site…I’m assuming there’s a large percentage of commenters/readers who own OBD-II (or even -I) readers already, so this is no big deal.
Would it be helpful to have in the infotainment? Yes. Is that a priority for me when shopping for a vehicle? Not in the slightest.
You can do whatever you want.
There are not enough of us to change anything that a big car company will do. Jason doesn’t have that many friends in a state legislature, and certainly not more than car dealers have.
I know what I will do on my next and expected last large purchase.
I don’t want a giant infotainment screen in my car. I have very few options, though. So, my next car will suck, that screen will die (we have a friend whose Tesla screen blacked out while driving, leaving us to wonder how fast she was really going) and will cost $1000s to replace.
(So, maybe not the last large $ purchase. Several annoying small ones afterward.)
Yes! Be the change you want to see, Autopian. Start reporting on the availability of built-in OBD2 displays in the cays you review.
Doh. Also the cars. Although if you would like to review cays as well, I would read that.
You know, if this group isn’t happy with the content, you can easily move on to some other site to troll. I appreciate what is produced here.
But how will Dealers and Mechanics be able to afford their boats? Think about all those hard-working people! And their boats!
…it’s entirely possible I spend too much time listening to Car Talk reruns.
Personally, I am very concerned about the deserving second homeless out there.
You can always switch over to Scotty Kilmer laughing like a hyena about his scan tool picking up 300+ data points on some dude’s car.
I think it would actually increase their business. Nothing better than a customer that doesn’t want to pay for diagnostics since they “know what is wrong” and only want you to replace the part that AI says causes that code.
Even better is the car that spits out 6, 12 or more codes even though they are all tied to one root cause. Seems like a good excuse to get out the parts cannon and start loading up the parts starting with the most expensive and labor intensive parts.
I got my pickup for cheap because the gov’t’s “professional” “technician” recommended to surplus the unit early due to multiple codes. I of course brought my OBDII dongle to the inspection, determined the root cause in a minute, went home and bid to win. I picked up the part on the way to pick it up, completed the purchase, fixed it in the parking lot in 5 min, cleared the codes and drove home CEL free.
Honda and Acura infotainment systems allow you to view the codes right from the screen.
Huh? For real?
Yeah it also comes up as a notification in the screen as well. It once notified me of my TPMS system failing because I was driving in cross winds that were so severe my car was basically crab walking. Another time it popped up a CEL and it told me directly from the screen I had a loose fuel cap (thanks full service gas station workers).
I don’t know if mine does that. The screen is tiny.
100%.
Strangely enough, the car company that was always most fiercely secretive about its service/repair procedures is now the most open… when put into Service Mode my Model 3 can not only do exactly what you describe, pull up fault codes in great detail, provide details on how to troubleshoot the issue, but allow you to access a LOT of adjustments/programming that is not normally open to mere mortals.
At minimum all OEMs should make the fault codes easily accessible.
It’s only fair since the DOGE bag stole all our private data.
Hardly an equitable trade, but I suppose it’s better than nothing
So, funny story. I work for a heavy equipment manufacturer that people love to hate recently because of Right To Repair concerns. Those people have no clue what they are talking about, and one example is that DTC’s are displayed on the in-cab display exactly as Torch is proposing for cars. They also generate alerts in our free web software and our free mobile app.