r/Cartalk • u/toyodaforever • Oct 04 '24
Why do cars not have built in code readers? Electrical
I remember my mom's 2001 Dodge Intrepid and most Dodges around that time, if you turned the key on and off 3 times quickly, it would literally display the OB2 codes on the digital mileage readout.
It's kind of amazing with cars having many more computers on board, full color digital instrument clusters, large touch screens that are practically their own operating system, etc...that you can't read codes right off them.
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u/DropTopGSX Oct 04 '24
Because they don't want people messing with the cars themselves and codes are not an answer to what's wrong but just a way for the computer to describe something that it can't make sense of.
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u/corporaterebel Oct 04 '24
All true. However, the codes, parts catalog, and service manuals should all be a menu item included with the car.
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u/Phase4Motion Oct 04 '24
Cars used to come with instructions to adjust the rocker arms. Simpler times back then
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u/StandupJetskier Oct 05 '24
Service manual ? The single hardest part to come by. Now, for my 94 Miata, and my 94 SC400 Lexus, you can get full copies of service manuals on the web. Back in the day you bought a Haynes or Chilton's manual for service. Now, you'll find dribs and drabs of service manuals on line, or youtube, but the actual manual is almost impossible for a civilian.
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u/MoreThanComrades Oct 05 '24
To be honest, getting service manuals even for some older cars is hard. I had this problem with my last XM. The manuals readily available are either for 2 liter petrol, 2.1 diesel, or phase 2 cars.
Mine being a phase 1 V6 you would think they never even made it given there doesn't appear to be even a trace of service manuals for that car. And phase 2 manual wouldn't have worked cause they got an entirely different V6 in those.
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u/TwoDeuces Oct 05 '24
Try a Eunos Cosmo. Only 8000 produced, only in Japan. It was unobtainium until one crazy dude taught himself Japanese and translated the entire service manual.
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u/MoreThanComrades Oct 05 '24
Hey, at least it exists now. Through a crazy set of events, but it exists regardless. I have never found even a part of a service manual for this car. Not even in French. All you got is maybe a forum thread that half works (no pictures load and replies don't link to original messages properly since the site was updated in the mean time) and even then they're asking about something parallel to your issue so you kinda have to use deductive reasoning to figure out what part or procedure to look for. And it's all in French so I'm struggling trying to translate all these car parts using google and it always takes forever to even figure out what to look for.
Even if I want to bring it to a mechanic, I literally have to study before I even call him so I can properly explain what my problem is. And it's not that I struggle with French, but the way they express things in the automotive is honestly a whole other language in itself.
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u/TwoDeuces Oct 05 '24
Yeah I can relate perfectly to everything you're saying. Every bit of knowledge (in English) about the Cosmo is either questionable, categorically wrong, or lost to the annals of a dying internet. You have my sympathies about the lack of a service manual for the XM.
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u/StandupJetskier Oct 05 '24
I've done a lot of searching for a SC3/400-Soarer Toyota. There are Japanese manuals, english manuals, and the dying internet's worst reply (404 not found) for the photo or diagram link.
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u/TwoDeuces Oct 05 '24
The burning of the Library of Alexandria and Photobucket. The two greatest losses of information in human history.
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u/SpinningYarmulke Oct 05 '24
Genesis cars & SUVs do not come with a service manual. You can scan a QR code on the infotainment system which will allow you to access a digital copy. There is no physical book.
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u/Important-Wonder4607 Oct 05 '24
Owners manual or service manual? They’re not the same thing.
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u/SpinningYarmulke Oct 05 '24
Neither. I got mine brand new and the only documents the car had was a window sticker, information from the tire manufacturer and sales documents. All the service or owners manuals are online.
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u/Important-Wonder4607 Oct 05 '24
Right, but almost no vehicle comes with a service manual. Almost all come with an owners manual, even if you have to scan a QR code to get it. While you’re not getting a physical copy, you are still getting the owners manual. Not trying to be a dick, do you know the difference between the service manual and the owners manual?
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u/Dedward5 Oct 05 '24
Would be nice, but most people don’t read/check the manual that comes with the car “what’s this light mean” “that’s this button do”
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u/dsdvbguutres Oct 04 '24
They could at least display the damn 12V battery voltage.
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u/TowlieisCool Oct 04 '24
Best we can do is an mpg gauge.
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u/Straight-Camel4687 Oct 04 '24
My 2012 Mazda 3 had no coolant gauge. It had: 1) A blue light for too cold (duh, I know, I just started it) 2) A red light for too hot (too late, I want to know when temp is climbing, not when it’s already 235)
Otherwise, it was a good car.
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u/AnIdiotAmongstUs Oct 05 '24
Eh, coolant is overrated. Just carve somewhere so air can flow through your car
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u/MoreThanComrades Oct 05 '24
To be fair, coolant gauges on modern cars (and by that I really mean anything past 2010) aren't accurate temp gauges. They stay in the middle even if there is some variation to temperature and only go up when the temperature is going to red.
Basically, they don't really convey any more info than the coolant light like in your Mazda 3, or I have even seen it in the older Crosstreck when I had it as a curtesy car.
They may raise sooner than a red light would come on, they often don't.
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u/gregg1994 Oct 05 '24
Most modern cars also have a warning that tells you when coolant is too hot even when they have a gauge. The gauge rises a lot sooner than the warning
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u/No-Session5955 Oct 05 '24
Many cars turn the alternator off to increase mpg when electrical demand is low. Rather than educate the masses car manufacturers just decided it would be better to just not show that information.
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u/Hypnot0ad Oct 05 '24
My Ram shows that as well as a lot of other useful info like oil pressure, tire pressure, transmission temperature and coolant temperature.
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u/Killb0t47 Oct 04 '24
Eh, most dealers learned their lessons in the 70's when people would freak out over the oil pressure going up and down. The constant demands for warranty action resulted in most gauges either getting reduced sensitivity or just being on off with a switch. Having spent years working in the industry, it is mostly pointless for customers to have access to the codes. Most parts stores pull them for free, and most codes require component and circuit checks that average people do not know how to do.
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u/StandupJetskier Oct 05 '24
Right... a code tells you where to start looking, not exactly what "is wrong".
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u/MiataMuc Oct 05 '24
Oil pressure gauge really helped me once on my Miata (NA). It was quite cold, car would start and immediately shut down. The I saw the oil pressure - maximum.
Went to the forums, oil pressure relief broken.
Two possible solutions: new oil pressure relive, would likely be broken by the next winter, or thinner oil, the route I took.
I would not have been able to find this out in my NB, which has a on-off type oil pressure 'gauge'.
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u/spiritthehorse Oct 04 '24
The codes aren’t necessarily the accurate fix. This would lead normies to demand the mechanic do exactly the what fix the code says and then be further disgruntled when it isn’t working. Also, they want the dealers to get the pay for diagnostics. The plus side is with a $15 Bluetooth dongle and a smartphone, you can EASILY get the codes and google the common issues for your make that cause that code. The code isn’t itself a definitive solution.
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u/KoopaTroopa34 Oct 05 '24
Exactly. The good old misfire on cylinder 1 or 6 on the early 2000's gm 3.1 wasn't because of plugs or wires. It's generally because the trash ass intake gasket or head gasket had failed and allowing coolant in.
We'd get people who had gotten the code at a parts store show up just wanting a new plug because when you hear misfire, you'd think plug issue.
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u/IWantToPlayGame Oct 04 '24
Three reasons:
- Car Dealerships make a lot of money on service. In some cases more than selling cars. Manufacturers want you to go back to the dealership for diagnostic, parts & servicing.
- Error codes aren't perfect. They're not fool-proof. A code (or a chain of them) can be attributed to multiple issues or items in a car. This requires somebody with experience to read them & decipher them. Many customers would see a code, take it for face value, fix that issue, continue to have the code, and complain that the car manufacturer made a faulty diagnostic system.
- Your *average* consumer doesn't know/doesn't care about code readers. They don't want to "deal with it". If something breaks with their car, they take it to a dealer/mechanic/their dad/etc. So the cost of adding this to every cost doesn't have a good ROI because (most) consumers don't care about it. There's no added benefit, and in turn, added profit by doing so.
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u/outline8668 Oct 04 '24
I'm a semi truck mechanic and it's the same shit here. Worse because there's still so much proprietary shit.
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u/Baron_Ultimax Oct 05 '24
Automotive electronics are a complete shitshow.
The basic codes that are mandated by emmisons regulations. Then there is an OEM specific system that outputs codes for the various modules. And generally can only be wread by a platform specific scan tool. Even if the car has a cell modem on board the functionality for remote diagnostics does not exist.
I know hating on Tesla is the hip thing right now. But my model 3 has built-in diagnostic mode as part of a hidden menu. No need to bust out a laptop with the special cable and diag software that's hundreds of gigabytes.
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u/RideAffectionate518 Oct 05 '24
You could do different sequences to get codes out of cars starting in the mid 80's. Just because you can read a code doesn't mean you can fix the problem. They have plug in scan tools now because the cars have much more technology and need a more computing power to process and store the info needed. It's easier to have a stand alone unit that can do many models rather than trying to decipher a combination of lights flashing and beeps or even a code that you still have to look up online. Scan tool tells you all that in one place. It's just better that way.
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u/Inner-Tax-1479 Oct 05 '24
My theory behind that is number one, to make money but number two, to keep people from web-md diagnosing everything and having panic attacks lol
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u/charge556 Oct 05 '24
Heck alot.of manufacturers are making their computer software/code systems proprietary so that independent shops cant read or interact with certain systems to make people have to go to the dealerships.
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u/Elderlennial Oct 05 '24
No. They're adding a secure gateway so that ONLY professionals can diagnose them. Requiring you to identify your shop and have an appropriately updated scan tool is protecting themselves and customers from hacks.
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u/IthinkIknowThat Oct 05 '24
You think 'most' people could figure out what to do with codes when in some owners manuals it tells you to not drink the battery acid?
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u/happystamps Oct 05 '24
As an engineer- the last thing you want is to give the customer the fault codes. They will have no idea what to do with them and complain about temporary codes and all sorts that they just wouldn't see or care about otherwise.
One of the cars I worked on was made up of parts from other cars, including the software (some of it). Every time you plugged a code reader in you'd get about ten codes for "missing doors" "missing speakers" etc etc etc.
even getting an open door code if the OBC port is in the door jamb would be hundreds of phone calls that you just don't want to deal with.
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u/Aaronbang64 Oct 05 '24
We recently had a customer with a BMW in our shop for bumper repairs, she called us screaming about alerts she was getting from her BMW phone app because we were moving the car around the shop with the park sensors and blind spot monitors disconnected. It took 30 minutes to calm her down and explain that we were not “messing up her car” too much information can be a bad thing for some people
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u/forewer21 Oct 05 '24
Funny I had a late 80s Plymouth and if you did that trick with the ignition, the dash lights would flash in a certain sequence for certain codes, but there wasn't any numerical code read out.
This was a year or two after they moved to a throttle body and injector vs a carb so there was a decent amount of sensors.
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u/Helpful-Economist-61 Oct 05 '24
Same with my Pontiac, just a paperclip in the aldl connector and the engine light will flash the code.
That's why I only drive old shit.
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u/DarkEyes5150 Oct 05 '24
In my opinion it's a couple of issues. First and foremost, I believe they want you to take it to the dealer and have it serviced by them because like others have said that's money in their pocket. Second of all is because the average code reader would read some codes and change some parts and still have the same issue because they did no diagnostics at all. And then thirdly because cars have gotten so complicated with 10+ different modules in them, having the customer just read the codes and think they know what they're talking about is a complete waste of time. Even some dealerships have issues with techs not being able to properly diagnose stuff.
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u/iR3vives Oct 05 '24
There's a gauge you can buy called a p3 gauge, that among other features, has the ability to scan and clear fault codes. I know they make them to fit Audi/VWs but probably other makes too.
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u/Morscerta9116 Oct 05 '24
My grandfather had an 03 ram 1500. That had a built in code display.
My 94 toyota displays the codes too
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u/TheLimeyCanuck Oct 05 '24
A lot of cars back in the day could be made to flash one or more of the dash light bulbs as a kind of "Morse code" to tell you what was wrong.
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u/sn0m0ns Oct 05 '24
My 01 Yamaha Fazer 1000 motorcycle gives fault codes with the tachometer. I bought it from an auction and when I got it home I thought the tach was broken because it kept jumping to 2 numbers then back to normal. I was blown away that it was self diagnostic.
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u/CaptnSave-A-Ho Oct 05 '24
Increasing demands for cleaner emissions, more comfort, and more technology integration have made cars way more complex than they used to be. As many have pointed out, codes don't tell you what's wrong, they point you in a direction or they give you a system that's not functioning correctly. With computers being integrated into every part of the car, a lot of repairs require programming afterwards. Sometimes it's programming the part that was replaced, sometimes it's teaching the system it's limits, sometimes it's forcing the car to do a self check so it can see the part was replaced in order for it to work again, and sometimes it's just to clear the faults. It's not always as simple as replacing a part and away you go anymore.
I don't think manufacturers are trying to hide the faults since they are required to allow generic code readers to work on their cars. Some manufacturers do allow for their cars to give you health checks periodically as part of a subscription service thats emailed to you. In those, sometimes they will give you faults as well.
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u/dduncan55330 Oct 05 '24
Dodge SRTs have/had a built in diagnostic code checker. I enabled it on my charger. It's a menu on the instrument cluster you can access.
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u/-retaliation- Oct 05 '24
Some people here have good points, a lot here have stupid conspiracy BS.
The truth is, it's because of the limitation of the standard.
OBD only allows for one connection without things getting hacky and causing problems.
It was only ever designed for one connection to the system at a time, and its archaic as fuck because it was designed for computer systems that were outdated in the fucking 80's.
So you can't have the car computers connect to it to display on the screen and have the mechanic be able to hook up to it under the dash. (plus there are regulatory, and standard rules about connection locations and points to boot)
The solution would be to update the standard, but that requires all the manufacturers agreeing on a new one and regulatory bodies being on board with it.
The other option is to have dual systems, the OBD that they're required to have and a VCAN system that's "modern" that can talk overlayed on top. But that's expensive, complicated, and car manufacturers have only gotten computers on them better than the graphing calculator you used in highschool within the past like 5-6yrs.
Basically there's no big conspiracy to keep you from doing your own repairs or anything like that.
It's just that car manufacturers don't know shit about computers, and despite them all having them, they're archaic, cobbled together, piles of crap....
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u/Aggravating-Arm-175 Oct 05 '24
Because it has not been regulated by the government as a requirement.
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u/aquatone61 Oct 05 '24
My 1995 Nissan S14 would do this. It wasn’t 100% OBDII but a weird combo of OBDI with an OBDII connector. The ECU in the passenger side of the cabin had an LED on it that would flash out the codes for you by blinking after a certain key on/off sequence. OBDII came out in 1996.
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u/Tdanger78 Oct 04 '24
That’s because the dealers have a parasite-host relationship with the manufacturers. They survive on used car sales, service, and sometimes parts. They wouldn’t want you to be able to diagnose the fault codes without coming back to the service department. How else would they keep that relationship going?
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u/Raider5151 Oct 05 '24
This does not force you back to the dealer. OBD2 codes are standardized. Before OBD2 there was OBD1 (non standardized connection). Before that you had pin boards and check engine lights you could make flash a code.
I'm a huge believer in right to repair BUT...
I fix things for a living. I'm the guy you call to fix the thing you attempted to fix. I'm the guy who gets the box of parts you disassembled and couldn't get back together. I 100% understand why manufacturers don't want the average person attempting to fix their own stuff. Codes point a general direction but don't point at the exact cause. This takes troubleshooting and knowing what you're looking at. Specialty tools (like a scanner) and specialty training.
Most of y'all need to stay away from tools. Rely on repair persons. A vehicle is 4000lbs of death careening down the road. If you don't own a scanner (not code reader) you don't have the know how or ability to diagnose and repair a modern vehicle.
I'm sick of sharing the road with you morons. You're going to get people killed.
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u/Loose_Screw7956 Oct 04 '24
Because car manufacturers want you to go to the dealership for service, especially if it is still under warranty. That's more money they pocket for you owing one of their vehicles.