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Any Open Source Solutions For DIY Auto Diagnostics?

Posted by kdawson on from the data-more-data dept.

slaxx writes "As an avid tinkerer, I really want to collect as much data about my car as possible. Using On-Board Diagnostics (OBDII) sounded great to me, but the pricetags of systems like AutoTap Scanner are a bit much for my college budget to handle. Are there any free, open source solutions available? What do Slashdotters do to tinker and record the inner workings of their own vehicles?"

20 of 270 comments (clear)

  1. To Expensive? by Anonymous Coward · · Score: 2, Insightful

    If $199 is to expensive for the hardware and software onyour Budget what do you expect to be able to fix on the car for cheaper?

    1. Re:To Expensive? by Anachragnome · · Score: 4, Insightful

      "The OBD-II codes didn't tell me exactly what to fix/replace on any of those but it greatly reduced trouble shooting time."

      THIS. Yes, IN CAPS.

      Scanners and shop scopes are GREAT for locating problems, but they do NOT replace a well-trained mechanic. Above poster makes it sound simple, but he already had an understanding of automotive tech. For example, using out-of-spec MAF readings to diagnosis an intake leak is one thing, but those readings could also be caused by intake valve issues, worn piston rings or a plethora of other things including a bad MAF sensor.

      My point is that an understanding of the underlying systems is still required.

      Don't expect a scanner, or even the information provided by one, to "fix" your car. They simply point you in the right direction (sometimes) and also allow you to verify the repair worked as planned.

      A side point. A cheap scanner will never have a "snap-shot" function, while a decent one will. This is CRUCIAL in diagnosing intermittent failures. Otherwise, you will be sitting there trying to make the problem occur while you have the scanner hooked up, often missing the 20ms failure. Blink and you miss it. A good scanner will store "frames" of info to go back and examine.

       

  2. As an engineer... by Anonymous Coward · · Score: 1, Insightful

    Absolutely nothing... there's a reason equipment that hooks into safety critical systems is so damn expensive.

    1. Re:As an engineer... by Jurily · · Score: 2, Insightful

      Agreed. Open Source is not a magic bullet.

    2. Re:As an engineer... by Excelcia · · Score: 5, Insightful

      Mixing high tech electronics with automotives has always struck me as the worst fusion of the old joke: "the difference between a computer salesman and a used car salesman is the used car salesman knows when he's lying". As an engineer it may seem like a good idea to you that the equipment is expensive, but how many mechanics are also engineers? Mechanics are often not even mechanics any more. They plug in the diagnostic and whatever it says is wrong, is what is wrong. Don't try and tell them that it doesn't make sense that a stretched timing belt is causing the shimmy coming from the front passenger wheel, darn it, that's what the computer says.

      No, the reality is that the reason the equipment is expensive is so that dealerships have a corner on the market. Post-sales service is one of the largest sources of dealership income. Which, if you think about it, is a truly sad state of affairs. Besides politicians, what is the one thing people are often most cynical about? It's auto dealerships. Because no matter how educated the average person gets about the way a vehicle works, a clever desk manager can always tell you the mechanic in the back plugged in a diagnostic and it said the "[techspeak] board indicated the [techspeak] [techspeak] has failed which [techspeaks] your ignition, and this is caused by road salt erosion of your [techspeak] which is obviously not covered under the warranty".

      No, making the test equipment expensive, or otherwise keeping it out of reach of the public is not the answer to either the technical issue of vehicle "safety" or the PR issue of cynical consumers. The answer is open standards, common test equipment, and education. This just doesn't do anything for dealership income, that's all.

    3. Re:As an engineer... by Thad+Zurich · · Score: 4, Insightful
      Anyone who allowed their company to build a car, in which the computer was safety-critical, with no mechanical fail-safes, needs to spend the rest of their lives in Gitmo being water-boarded. And no, there's no *good* reason that such equipment is expensive , other than proprietary protections for the vendor. The equipment used at the factory does not do anything special to ensure the product operates safely; only the engineering simulations do that.

      That said, the foregoing does not mean it's a good idea for the casual mechanic to diddle with his car's computer, in part because it was probably optimized in interdependent ways that he has no chance of figuring out, because they only made sense serendipitously when being coded.

    4. Re:As an engineer... by Pojut · · Score: 5, Insightful

      Mechanics are often not even mechanics any more. They plug in the diagnostic and whatever it says is wrong, is what is wrong.

      Speaking as a former mechanic, fuck you very much. OBD II codes serve to provide you a place to look, nothing more.

      Say for example the code is a misfire on Cylinder 3. Great. Do you have any idea how many different things can cause a misfire? It could be the ignition coil...or the spark plug...or the throttle body being clogged...or it could be a freak-one time thing that can't be replicated...or it could be something entirely different. Same thing with an O2 sensor. Just because it says "O2 Sensor Three is reading incorrectly" doesn't necessarily mean the O2 Sensor is bad. You could have bad wiring, the air/fuel mixture could be throwing off the reading, the person could have just put bad gas in it, or again many other possibilities. Have fun diagnosing that electrical problem that keeps causing the ECU to think that your Crank Positioning Sensor is bad (causing it to throw a code and making the check engine light come on), when in fact the sensor itself is perfectly fine.

      It's not as simple as just "this is broken, please replace it." Many dealerships do this, but real shops do not.

      Because no matter how educated the average person gets about the way a vehicle works, a clever desk manager can always tell you the mechanic in the back plugged in a diagnostic and it said the "[techspeak] board indicated the [techspeak] [techspeak] has failed which [techspeaks] your ignition, and this is caused by road salt erosion of your [techspeak] which is obviously not covered under the warranty".

      If you go somewhere in which the guy up front tells you that, you demand that they put your car back together, take it off the rack, and go somewhere else. You didn't take your car to a shop, you took it to a lie.

      --
      Living With a Nerd
    5. Re:As an engineer... by ddillman · · Score: 3, Insightful

      Translation of GP: You're not smart enough to bother looking at this, it's way too complicated. And besides, I make my living working on this stuff, I wouldn't want to lose any income because you learned how to fix your own stuff!

      --
      Little girls, like butterflies, need no excuse. -- L. Long
    6. Re:As an engineer... by ddillman · · Score: 4, Insightful

      Yeah, it still is. People have been working on, and repairing, their own safety critical equipment as long as there have been cars. Brakes are definitely safety-critical. I have done mine more than once over the years as a simple example. Just because it's safety-critical doesn't mean people can't learn how to DIY repairs, as long as the information is available. All this ODBII secrecy is just for the auto industry to extort money from the auto owners.

      --
      Little girls, like butterflies, need no excuse. -- L. Long
    7. Re:As an engineer... by ddillman · · Score: 2, Insightful

      If you go somewhere in which the guy up front tells you that, you demand that they put your car back together, take it off the rack, and go somewhere else. You didn't take your car to a shop, you took it to a lie.

      You're right on this. However, it's near impossible to tell up front whether the place you've taken your car is a shop or a lie, since most of them look basically the same, and you only find out after your car is in pieces up on the rack which one this particular establishment is. Which is where the cynicism of the poster comes in - so many 'shops' are 'lies' that the average consumer is just assuming until proved otherwise that ALL shops are lies.

      --
      Little girls, like butterflies, need no excuse. -- L. Long
    8. Re:As an engineer... by Pojut · · Score: 4, Insightful

      You're both wrong.

      I'm a former mechanic because 5 years ago, I fractured my left and right ulna, as well as navicular fractures in both wrists. If you can tell me how to work on cars with injuries that won't fully heal for years in both wrists, I'll be glad to do it.

      To the AC, I didn't want cars returned to me, which is why I always fixed what was wrong and not what I was told was wrong by a computer.

      --
      Living With a Nerd
    9. Re:As an engineer... by Pojut · · Score: 5, Insightful

      From my original post:

      Same thing with an O2 sensor. Just because it says "O2 Sensor Three is reading incorrectly" doesn't necessarily mean the O2 Sensor is bad. You could have bad wiring, the air/fuel mixture could be throwing off the reading, the person could have just put bad gas in it, or again many other possibilities.

      Have a nice day!

      --
      Living With a Nerd
    10. Re:As an engineer... by sootman · · Score: 2, Insightful

      > Speaking as a former mechanic, fuck you very much.

      I'm glad you were a good mechanic, but this is one of those cases where "it's just the 99% that makes the other 1% look bad." Everyone knows that finding a good mechanic is like finding a needle in a haystack--it's been a cliché for decades and it's totally true. I just spent several hundred dollars across two visits to find out why the "check engine" light was on.

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    11. Re:As an engineer... by thrawn_aj · · Score: 1, Insightful

      Many dealerships do this, but real shops do not.

      and

      If you go somewhere in which the guy up front tells you that, you demand that they put your car back together, take it off the rack, and go somewhere else. You didn't take your car to a shop, you took it to a lie.

      Ah. 'The no true scotsman fallacy'. OP was specifically addressing dealerships if you look at it again. The attitude above bugs the hell out of me. I agree with you that it's not as simple as reading the codes and a lot of critical thinking is needed to accurately diagnose the problem. I just maintain that the mechanics' horseshit has reached the point where I'd trust a lawyer before I trust a fucking mechanic to be honest with me. Fucking crooks the lot of them and the honest ones are usually just honest 'with people they know'. They make up their margins with customers off the street.

      The point, as always, is that service departments in dealerships (and other shops as well) need to be hella regulated by at least 3 different agencies, with monthly audits, starting with the assumption that every single one is a den of thieves. Douchenozzles. Now, they don't even let you into the work area anymore (unless they "know" you) using some convenient OSHA rule and insurance crap and concerns for your "safety", unless you insist and threaten to take your car elsewhere.

      So, tell me this. How is it suddenly ok, just for this one profession, to blame the victim for not being sufficiently observant and knowledgeable. The response always is, "well, if you don't know your car well, you can't blame them for robbing you blind." Though it's not stated that way, that's the essence of it isn't it? Well, fuck that. I wish all mechanics were treated like that by their doctors. Well, if you don't know your anatomy and basic physiology and epidemiology, don't blame us if the doctor does unnecessary surgery on you or prescribes expensive and unnecessary medications. Idiots. I have tremendous respect for mechanics' troubleshooting skills, but zero respect for their sense of ethics.

      And before people jump in with, "well, MY mechanic is honest with me"; that's my fucking point. He is, because he probably rips off people he DOESN'T know. That sort of corrupt sense of ethics used to be reserved for the highest echelon of politics. It's sad that now it's considered commonplace and even ok ("caveat emptor" say the douchetards. BAH!).

    12. Re:As an engineer... by Anonymous Coward · · Score: 1, Insightful

      Would you make that same statement in reference to the $15-an-hour kids working at most dealerships these days? Plug it in, get a code, look it up, fix it, send it back. It comes back? The customer must be wrong!

      Would you make that same statement in reference to a large percentage of mechanics out there who hire these same kids to come work for them?

      Many mechanics are no longer engineers, but rather tool monkeys. I know this in part due to my experience as both a mechanic and a computer repair technician. You spent 5 hours breaking that down to fix it? Well, great. You can only charge 2.5 hours of labor (because the customer will think it's too expensive), plus the cost of parts (which you sell near-cost anyways, because either, again, "it's too expensive", or "I can get it somewhere else cheaper"). Nowadays I'm a software engineer, which still has value in the marketplace. But I tell you now; in 20 years, when "everybody" knows some scripting language and can build their own rudimentary programs, I'll be struggling to make ends meet just as much as mechanics or TV repair guys do today. Because what I know (the "right" way) won't be worth jack anymore.

      Why should mechanics try to hire real, educated, problem-solving engineers? They may have been trained engineers themselves at one point (the Car Talk guys, as an example, went to MIT for pete's sake), but they can't afford to hire those people to work for them when it's more cost-effective to train people themselves, sometimes with better or worse results. Same thing at Geek Squad and all like institutions (well, less the experienced engineer at the top). So while you may be right when applying this "trained engineer" image to yourself, it really doesn't seem to apply to many dealerships or mechanics out there, and the issue has crossed industries (into the consumer electronics domain; why fix it when I can buy a new one for about the same price)?

      So sir, perhaps you should reconfigure your "fuck you very much" to apply to mass production, rabid consumerism, and cheap labor? It would be more fair, I believe.

    13. Re:As an engineer... by Pojut · · Score: 2, Insightful

      I just maintain that the mechanics' horseshit has reached the point where I'd trust a lawyer before I trust a fucking mechanic to be honest with me. Fucking crooks the lot of them and the honest ones are usually just honest 'with people they know'. They make up their margins with customers off the street.

      Sadly, I must agree with you. The shop I worked in prided itself in being honest with its customers (the first time a manager caught a mechanic trying to cheat a customer, they were fired on the spot. No second chances.) Despite our reputation and huge numbers of loyal customers, it was always very difficult to get new customers to trust us for the very reasons you outlined.

      The point, as always, is that service departments in dealerships (and other shops as well) need to be hella regulated by at least 3 different agencies, with monthly audits, starting with the assumption that every single one is a den of thieves. Douchenozzles. Now, they don't even let you into the work area anymore (unless they "know" you) using some convenient OSHA rule and insurance crap and concerns for your "safety", unless you insist and threaten to take your car elsewhere.

      This was something else we prided ourselves on. It's your car we were working on, and as such you had every right to see the problem yourself and, if you promised to not get in our way, even watch us do the work start to finish should you wish to. ("not get in our way" means not standing right next to us. Questions, conversations, all of that was fine...but if we had to work around you, back in the waiting room you went.)

      So, tell me this. How is it suddenly ok, just for this one profession, to blame the victim for not being sufficiently observant and knowledgeable. The response always is, "well, if you don't know your car well, you can't blame them for robbing you blind." Though it's not stated that way, that's the essence of it isn't it?

      We would always explain to people that when you bring your car into our shop, you aren't paying us to fix your car/replace your parts for you. You are paying for our knowledge of how to do those two things properly. Anyone can use a torch, or resurface a rotor, or make a custom exhaust out of straight pipe. Not everyone can do it properly. We always tried using simple analogies so that people had a better understanding of what was happening (my favorite being our description for drum brakes, describing the "drum" as a salad spinner and the shoes as "hands" or "the little lever you pull to stop it from spinning".), but sadly many new customers would accuse us of talking stupid to them, and acting like they were morons. It's a very fine line you walk, for sure.

      I have tremendous respect for mechanics' troubleshooting skills, but zero respect for their sense of ethics.

      Sadly, many people are under the impression that cars are more difficult to understand than they really are. As a result, few people take the time to famillirize themselves with even simple procedures, which in turn allows mechanics to prey on the ignorant with reckless abandon. Again, it was for this reason that we always took the time to try to explain to people how something functioned, why it went bad on their car, and what steps are required to prevent it. The way we saw it was if we could pique the interest of a consumer and make them realize that hey, these things really aren't so complicated, they might take some time to learn about them and reduce the chance they would get ripped off should they go somewhere else. Regardless, we had a zero-tolerance policy regarding ripping off customers. The owners of our shop would rather we turn away work (i.e. "Ma'am, I could fix this, but it would cost more than this car is worth. I wouldn't suggest putting any money into this thing) instead of taking money from people that we shouldn't.

      And before people jump

      --
      Living With a Nerd
  3. bad idea by Anonymous Coward · · Score: 2, Insightful

    I'm all for tinkering, and tinkering with cars used to be a great hobby. But tinkering with proprietary chip sets - with consequences not only your driving experience, but on the safety of others around you - without the proper equipment strikes me as a uniquely bad idea.

    1. Re:bad idea by kiwieater · · Score: 2, Insightful

      Tinkering? The whole point of these scanners is to read information and help diagnose problems.

      He could do more harm to the "safety of others around" him by advancing the ignition curve, leaning out the mixture, and melting the piston crowns. Or - if he had less sense and went about it the wrong way - working on the assumption that more fuel = more pwer, thereby flooding the followers on the road with a stream of unburnt fuel.

  4. 1. Complete nonsense; 2. google ELM327 by name_already_taken · · Score: 2, Insightful

    I'm all for tinkering, and tinkering with cars used to be a great hobby. But tinkering with proprietary chip sets - with consequences not only your driving experience, but on the safety of others around you - without the proper equipment strikes me as a uniquely bad idea.

    You've apparently got no understanding of what the OBD II interface lets you do.

    OBD II lets you read trouble codes and operational data (sensor values, fuel integrator, ignition timing, etc.), and lets you clear trouble codes.

    That's it. There's no danger at all. You can't alter anything other than clearing trouble codes.

    To the original poster, google for "ELM327" to find the hardware, and "ELM327 software" to find software, including many free apps that will use the ELM interface to talk to OBD II.

    I use a free app on an old Palm with an ELM327 adapter I bought off of eBay for OBD II work. Works great. I paid a little more for one that works over Bluetooth; the less expensive varieties can be plugged into an RS232 port on a laptop (old, cheap laptops are powerful enough and are more likely to have an RS232 port).

    The ELM 327 is fully documented and you can write your own software to talk to it. The datasheet is here: http://www.elmelectronics.com/DSheets/ELM327DS.pdf, ELM's OBD product page is here: http://www.elmelectronics.com/obdic.html.

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  5. Re: Too Expensive? by frisket · · Score: 3, Insightful
    I don't want to tinker, but if I fix something simple like an air filter, I want to be able to reset the console warning lights.

    Currently you need a specially-adapted laptop, a highly proprietary cable, and some very expensive software. Garages can afford this: individuals can't.