Hello there and welcome to the BMW Car Club of America.

If you are a BMW CCA member, please log in and introduce yourself in our Member Introductions section.

OBD II Code reader/reset tool

Discussion in 'DIY (Do-It-Yourself)' started by Wronsky, May 27, 2009.

    • Member

    Wronsky

    Post Count: 3
    Likes Received:0
    Any suggestions on which OBD II code reader to buy? Cheapest best? More info for more bucks? It would be nice to know what's going on when there is a check engine light calling for my attention in my E39 530i or Z3 2.8 whether I attempt to fix it myself or take in to the shop. It looks like one diagnosis might recoup the investment.
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Unless you buy the professional readers they are really not going to tell you all that much. You will end up replacing parts that might not be faulty. So unless you pony up to the pro level, really the only benefit is to reset codes including oil service. IMHO :)
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    + several hundred

    vtx guest

    Post Count: 56
    Likes Received:0
    Just out of sheer curiosity, is there anyone that has a first hand experience with this tool:

    http://devtoaster.com/products/rev/index.html

    Actually, it's not the iPhone app I'm interested in, but the bluetooth or WiFi enabled transmitter that I can plug into the OBD port and just let it be there. From their hardware page:

    http://www.plxkiwi.com/kiwiwifi/hardware.html
    http://www.obd-2.de/eShop/index.php?main_page=product_info&cPath=1_4&products_id=2&language=en
    http://www.obdkey.com/wifi/index.asp

    More than once I've felt tempted to just get the dumbest piece of hardware that is able to communicate with OBD and just write the driver for it - but every time the problem that made me want to do it went away before I got to it.

    Do I understand correctly that even the BMW systems available through the connector have their specifications open and available, or will have them open with all thies Right To Repair stuff coming? Where are the protocol specifications?

    There used to be openbmw.org that was dedicated to this very topic, but then (my best guess) their domain registration lapsed and they got hijacked by a domain parking troll (see http://whois.domaintools.com/openbmw.org), and they dropped off the face of the Earth - where are they now? Same with openbmw.com. Damn.

    I guess I'll just have to bite the bullet, buy one of those gadgets and start working on writing that app - it would only be really nice to know if the tool was capable of talking to BMW specific systems on a hardware level, that's all.

    adsingl guest

    Post Count: 5
    Likes Received:0
    Two thoughts

    I've gotten my money out of my Peake Research tool, which will read standard OBDII and specific BMW codes. But even with the more advanced tools, there is some discretion with deciding what part relates to what code that can cost a lot in shotgunning parts. But it CAN save from some simple and common diags like O2 sensors or point to a coil, etc. So one "win" and you've likely recovered the time and money to go to dealer and get a diag read, depending on their rates in your area and any distance or bother in getting there. Early in my BMW maint experience, I went to the dealer to see what they could tell me additionally to my "coil number 4" error on the peake tool. I was hoping for some tranny codes (another problem at the time), and had already switched coils so I knew it wasn't the coil.
    Their diag said "coil number 4", but they recommend doing all coils. This 1. didn't tell me anything I didn't already know and 2. would NOT have fixed the problem. There were no tranny codes either, even though I was getting a message and having shift problems (I bought a used tranny ecu; later it turned out the battery was probably the problem (loose connection/intermittent), so: 1 "win" and 1 "loss" where I bought something I didn't need.

    Also, you can go to autozone (probably other auto parts stores) and get most of these standard OBDII codes read for free as well.
    Good luck with your decision
    ADS

    adsingl guest

    Post Count: 5
    Likes Received:0
    Coding dev drivers and such

    OBDII and some of the comm protocols are mandated by US smog laws and are open.
    Everything past that, like proprietary error codes for options or even extra sensors, IBUS, etc, (and whatever the latest bus is) are all proprietary, but often get reverse engineered.
    ADS

    adsingl guest

    Post Count: 5
    Likes Received:0
    Coding dev drivers and such

    OBDII and some of the comm protocols are mandated by US smog laws and are open.
    Everything past that, like proprietary error codes for options or even extra sensors, IBUS, etc, (and whatever the latest bus is) are all proprietary, but often get reverse engineered.
    ADS

    vtx guest

    Post Count: 56
    Likes Received:0
    FYI: At least Checkers doesn't offer free scanning anymore. The caveat is, they will give the tool to do it yourself.

    A shop guy showed me the internal memo (which he shouldn't have done, but thanks to him anyway) that literally said:

    - no more performing code reads, for liability reasons;
    - if the customer asks for the tool, give it to him.

    I guess you have to explicitly ask.

    I won't be surprised if other stores follow suit, in this lawsuit-happy world.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    That makes sense because often they will say "it's an O2 sensor code" and someone will pony up a couple of hundered for O2 sensors only to find out that didn't fix it.
    You cannot access stuff that is not emissions related on a BMW with a normal OBD2 scanner. Trying to crack the protocols is difficult at best. I think Autologic and Launch must have some sort of contract with BMW to buy the info, so finding that in the 'net is going to be impossible. Even with a Launch X431, you can't program anything. Autologic at least gives you free updates during your yearly subscription, and allows you to program with the latest BMW releases of the control module software. Since they have so much invested, there is no way they will help anyone crack the protocals. It's all about $$$.

    vtx guest

    Post Count: 56
    Likes Received:0
    I'm not holding my hopes too high, but there's been some talks about "Right To Repair Act" recently that is allegedly supposed to make automotive manufacturers open the specifications. Of course there will be struggle and screaming, but at least some stuff will be open as a result.

    The $64,000 question for me now is - which is the dumbest and the cheapest OBDII interface hardware adapter that is capable of talking to all devices connected to the bus, and is capable of exposing that to me through USB, Bluetooth or WiFi so I can do something with it. That's all I need to start working.

    I guess the question is rhetorical and I'll have to answer it myself :)
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    http://www.engstrom.net/J2534-Pass-Thru-Interface-for-BMW-p/pcr-8707sd.htm

    The BMW Pass thru tool is about the only thing I know that is "cheap" and will talk to all the systems in the car. The only reason more people don't use it is that it is slooooow. It hooks up to a GT1 emulator somewhere in the world, and I have read that if you lose internet connectivity for even a little bit during programming that you can brick the control modules. All of them at once, in fact. For the same reason you will need a regulated CLEAN power supply of at least 50A to supply power to the car during programming, though interfacing can be done on battery power alone. That alone costs about $450-550.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    no regular OBD2 reader will talk to all control units.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15

    vtx guest

    Post Count: 56
    Likes Received:0
    Let me give you this example: you plug into an Ethernet socket. There are many systems behind (server, printer, router, etc.), but you (on the application level) can only talk to those that you are aware of and are aware of protocol to communicate with.

    However, the Ethernet card you've plugged into the socket doesn't care, and can potentially talk to any device - on Ethernet level.

    The OBDII equivalent of the Ethernet card is what I am looking for. Unfortunately, it takes time and resource to figure this out (days and weeks, if not months) so I'll be spinning my wheels for a while (have day job to take care of, too), but I have a deep suspicion that those devices links to which I've put into message #4 (http://bmwcca.org/forum/showpost.php?p=26215&postcount=4) are, in fact, that equivalent, and I just need to know how to make them talk to the right system.

    Now, I would certainly agree that the part that stands behind the hardware interface controller may not be capable of interpreting some interface protocol subsets, but that's a question on a different level.

    Now, let's suppose for a second that damn, there is not, indeed, such a chip (note, the chip - interface controller, not the reader) on the market today. How big is the market for such a device? Would it make sense to manufacture it DIY? I am willing to put my efforts into the software part, and there is someone I know that is perfectly capable of taking care of the hardware part, but man, it may just not be worth the effort if there's not enough demand. I'm afraid there's too few people that a) drive BMWs and b) are technically capable enough of realizing the need to have a decent OBD reader.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    My posts are back. Yay!
    Most of them physically don't have the pins necessary to communicate with all systems. The Launch and Autologic connect through the big round connector under the hood when present, and do not have full functionality if connected through the OBD2 port on pre-2000 models. After that they connect through the OBD2 port, but there are more pins that are not connected when hooked to a normal OBD2 scanner. The Snap-On MT2100 requires a special circuit board (they call it a "personality key") and connector to use on BMWs through the OBD2 port. However, you still cannot access all systems, but you can read info on some of them. Maybe that is a place to start, but, again, Snap-On is not going to help you since they paid a team of people to write the software and troubleshooting info for BMWs (I know one of them.) Best of luck, and let us know how it is progressing. Lemme know if you have any other questions about scan tools and such.

    vtx guest

    Post Count: 56
    Likes Received:0
    O! Now we're getting somewhere.
    What about post-2000?

    Another question - how many system connectors other than OBD2 are there? (treat it as rhetorical if you wish, for I do realize this discussion gets way too deep)
    Definitely is.
    I don't even know if I want to pursue this - it is surely tempting as a technical challenge (isn't that why we're all here? :)), but it can quickly turn into a second-shift job, not sure if I want that to happen.
    Thanks for the offer, will try not to abuse it.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    Post 2000 (I forget the cutoff month) hooks up through OBD2 but, as I said before, there are more pins than a normal OBD2 scanner will use (but the plug is the same as mandated by the OBD2 spec), so you will have to try to crack the system with hardware and software. There are no other connectors needed to service BMW electronic systems. Big round for earlier cars, OBD2 for later cars. Where are you located? I may know someone near you that can show you the hardware.

    vtx guest

    Post Count: 56
    Likes Received:0
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    Some of those pins may be populated for other purposes left to the manufacturer as allowed by OBD2. Those are the ones you need to find in the BMW wiring digrams. Some of the pins listed that work with one protocol are populated with other signal/power lines on cars that do not use the same protocols. That is why Snap-on has personality keys. If you use the wrong key with the wrong car, you can let the smoke out.

    GZoghby guest

    Post Count: 1
    Likes Received:0
    Code Reader Tool

    In my opinion, the Peake Research code reader is a great choice but you have to evaluate your own requirements. The company specializes in BMWs and has been around for 19 years.
    http://www.peakeresearch.com/fcx3.htm

    The tool is easy to use. It makes it easy to read and reset Check Engine Light (CEL) codes. It reads both industry standard OBD-II and proprietary BMW codes. The code booklet has served me well many times for my 1996 328is (E36). Most people will find that the tool will pay for itself in just a couple repair operations which otherwise would have required a trip to the BMW dealer.

    However, reading the codes is just the beginning of the repair operation. Although any one code has a specific definition, often there are many possible failures that could trigger the code.

    For example, I recently got:
    E4 = O2 sensor adaptation limit, Cyl #1-3
    E3 = O2 sensor adaptation limit, Cyl #4-6
    CA = O2 sensor control limit, Cyl #1-3
    CB = O2 sensor control limit, Cyl #4-6
    It turns out the problem was caused by cracks in the rubber air intake boot after the mass air flow sensor -- not the O2 sensor. Which makes sense when you realize, a crack after the MAF sensor means extra O2 was getting into the previously measured air. When the O2 sensor feedback indicated the mixture did not burn as expected, the computer adjusted the mixture up to its limit.

    So, you still have to inspect the engine carefully and analyze the issue to diagnose the problem correctly.

    In my research, I also evaluated the higher end products usually called "scan tools". They range in price from expensive $500 to only sensible for professional mechanics $2000.

    BTW -- I bought my tool for $149. from Bavarian Autosport who resells the Peake tool under their own brand:
    http://www.bavauto.com/

Share This Page