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Thread: 98 e38 obd2 unable to connect

  1. #1
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    98 e38 obd2 unable to connect

    Just bought the car, previous owner didn't keep good records and doesn't know much about it. Battery wouldn't hold a charge and replaced it with a new one. Check engine light is on, fuses seem to be fine. 20pin connector under the hood is connected and looks to be in good condition. Tried multiple OBD2 scanners, all come back with an unable to connect/read error.
    OBD2 port is getting 12v on pin 16, however I'm unsure what the other pins should be. Any ideas on what's going on? I've seen mixed information online, some people say that obd2 is only for smog testing which doesn't sound right to me. If someone could set record straight I would greatly appreciate it. Won't be able to test from the 20pin until Tuesday/Wednesday.

    Edit: Main issue is the car is in limp mode(trans failsafe prog.), hoping the codes will give me more info on why.
    Last edited by Toomuchsugar; 01-21-2019 at 01:20 AM.

  2. #2
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    Moved to E38 forum
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  3. #3
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    Obd plug is for air bags, etc. not for dme. look into obd threads there is a mod you can do to the 20 pin to make obd plug work.

  4. #4
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    obd2 scanner doesn't connect at all, no functionality what so ever. Is that normal for this car? after 96 obd2 was made standard, I would expect some functionality from this port even if limited.

  5. #5
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    The under-hood 20-pin diagnostic port allows connection to all modules on the E38. Later models had an additional OBDII port in the cabin - and that was restricted to diagnosing the engine and gearbox. The additional OBDII port was added to allow SMOG tests to be made as was mandated by CARB.

    https://www.meeknet.co.uk/e38/obd2-bmw20.pdf
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


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  6. #6
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    Tiimm’s right. Like I said there is a mod that can be done to the 20 pin that will allow full access through obd port

  7. #7
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    https://www.bimmerforums.com/forum/s...endly-OBD2-mod

    I assume this is the one you guys are talking about? I'll give it a try and see what happens.

  8. #8
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    Hopefully this works and doesn't short something
    20190121_134457.jpg

  9. #9
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    No luck, still can't read from obd2. All scanners just load for a while and say they can't connect. Also noticed the check engine light isn't on when the car is running, only during bulb check. There should definitely be a check engine light on.

  10. #10
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    98 e38 obd2 unable to connect

    Bummer time to pull the dme and check for connection problems. And check fuses too

  11. #11
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    Fuses are fine, any way of testing dme without special tools?

  12. #12
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    98 e38 obd2 unable to connect

    Not sure on that, but should check to see if you have water damage to the dme connections.

  13. #13
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    Use an older OBD scanner. I have an old one I use for the E36 and E38 and I connect using the port inside the car. Tried using a newer one from Amazon on the old cars and just got a communication error. Vice versa when I try to scan the X3 - old scanner does not work, new scanner does.

    But for your problem you are better off using INPA and connecting to the round pin under the hood. The Mod above will allow you to use INPA when connected to the port inside the car.
    Last edited by clarkitect; 01-22-2019 at 10:31 AM.
    2000 740i Sport | 2004 330xi | 1988 325i Vert | 2003 Z4 2.5 | 1995 Ford F150 | 2018 GTI

  14. #14
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    There seems to be a lot of options out there for Diagnostic systems outside of the standard obd2, most of which goes over my head.

    I'm currently looking at something like this, comes with a ADS/ODB 20-pin adapter. My current plan is to find a windows xp laptop, get a k+dcan kit off Ebay and go from there. Does this seem right, are there better alternatives?
    Last edited by Toomuchsugar; 01-23-2019 at 05:23 AM.

  15. #15
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    Quote Originally Posted by Toomuchsugar View Post
    There seems to be a lot of options out there for Diagnostic systems outside of the standard obd2, most of which goes over my head.

    I'm currently looking at something like this, comes with a ADS/ODB 20-pin adapter. My current plan is to find a windows xp laptop, get a k+dcan kit off Ebay and go from there. Does this seem right, are there better alternatives?
    Bimmergeeks

  16. #16
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    I purchased off eBay, don’t waist our time. I’m stuck with a system that barely works and is missing all the key codes. Had to reconfigure most of it and still have problems.

  17. #17
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    Sorry?

  18. #18
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    No tears, lol. I will admit that the problems I’ve had do make me more knowledgeable. But bimmergeeks is proven and widely used. Plus you can use software on any computer no need to buy another lap top

  19. #19
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    I don't have a laptop, don't plan on lugging my desktop down to the garage. Figured I would go for something that wouldn't have driver compatibility issues. I'm confused because you're said "don’t waist our time." did you mean don't waste your time, as in mine, by buying from ebay rather than bimmergeeks?

  20. #20
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    Sorry eBay, were my rant started from. If you don’t have a laptop you could also consider rheingold too. Bimmergeeks has the best d/k can cable and free software

  21. #21
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    Quote Originally Posted by Sundaycruzer View Post
    Sorry eBay, were my rant started from. If you don’t have a laptop you could also consider rheingold too. Bimmergeeks has the best d/k can cable and free software
    Pretty sure rheingold is only for a laptop? Most of what is on Bimmergeeks that's not for laptops is for newer cars or the cables and software links to install on laptops that will work on the older cars.

    For what it's worth, I think your best bet is to get a cheap laptop running windows 7 (no need to downgrade to XP) and get the software download from bimmergeeks. Not hard to get it going. You can buy your cable from them, or this ebay link I got from a member on here who has helped me out a lot with INPA. I agree you never know what you will get on ebay but this came from a trusted source.

    https://www.ebay.com/itm/123208665299?ul_noapp=true
    2000 740i Sport | 2004 330xi | 1988 325i Vert | 2003 Z4 2.5 | 1995 Ford F150 | 2018 GTI

  22. #22
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    Quote Originally Posted by clarkitect View Post
    Pretty sure rheingold is only for a laptop? Most of what is on Bimmergeeks that's not for laptops is for newer cars or the cables and software links to install on laptops that will work on the older cars.

    For what it's worth, I think your best bet is to get a cheap laptop running windows 7 (no need to downgrade to XP) and get the software download from bimmergeeks. Not hard to get it going. You can buy your cable from them, or this ebay link I got from a member on here who has helped me out a lot with INPA. I agree you never know what you will get on ebay but this came from a trusted source.

    https://www.ebay.com/itm/123208665299?ul_noapp=true
    Rheingold is basically ista/istp. And will do e/f generations and rheingold can sell it already downloaded on their laptop ready to run. Bimmergeeks is fundamentally just software, will have to still download sp-daten and etc before it will function.

  23. #23
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    You can also buy a whole laptop set up with software from member Trasportador. I think he charges $200 for the whole deal. Probably still need to buy a cable but pretty sure he would make a recommendation.
    2000 740i Sport | 2004 330xi | 1988 325i Vert | 2003 Z4 2.5 | 1995 Ford F150 | 2018 GTI

  24. #24
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    So bimmergeeks doesn't have a abs/obd 20 pin adapter, so that doesn't work for me.

  25. #25
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