OBD-II scanner won't read my car's computer

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  1. #1
    My pornstar name came up "Jay the Snork."
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    OBD-II scanner won't read my car's computer

    My 98 1.8t is running great, no CELs, or any other issues that i know of (except one, i will get to that) but i had to take it in for annual smog testing. I went to two different places, but neither could get their diagnostic machine to get a reading on my car's computer.Any ideas why?

    My ABS controller is shot, but i can't believe that would interfere with a scan tool, would it? Or, is it possible that my OBD port is just busted/ disconnected somehow and needs to be replaced/repaired ? Has this happened to anybody else? I didn't see anything like this while searching the forums.
    I have 30 days to get this sorted out before i have to take my car back in for a retest, so the sooner the help the better. thanks in advance.

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  3. #2
    My pornstar name came up "Jay the Snork."
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    did more searching and found thread saying it could possibly be due to aftermarket radio/head unit? Any ideas any one?

  4. #3
    PassatWorld Staff
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    Bump.

    I'm no expert, but I thought the aftermarket radio issue wasn't an issue on the older ('98) cars.

    The ABS module is a different module than the ECU. Emissions should only check the ECU. I don't see why a busted ABS module would cause OBD-II scanner to fail. But who knows? Not me.

    Do you have anyone close to you with a VAG-COM? That might tell you something - if a VAG-COM doesn't work, you may indeed have a cable problem.

    Have you ever had the lower dash off? If so, the OBD wires may have gotten pinched, or pulled off the connector.

  5. #4
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    I've seen where the connector got pushed up a little and when you plug the scanner in, it can not read your ECU.

    Take off the fuse side cover and reach in to re-seat the connector. Works better if you have girly arms

  6. #5
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    Quote Originally Posted by mfitz
    did more searching and found thread saying it could possibly be due to aftermarket radio/head unit? Any ideas any one?
    The local shop I use told me they would not connect their scan tool to a VW with an aftermarket stereo because they had ruined two tools and refuse to fry a third.

  7. #6
    My pornstar name came up "Jay the Snork."
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    thanks everyone. i hope that it is simple as a loose connector. i will check it out tomorrow in daylight. Does anybody else know for sure if the aftermarket radio problem is confined to newer models?(If so, chalkup another point for the AEBs )

    if that is the problem, i do have the original radio and can put it back in if necessary.It would just be a pain in the ass, but at least it would be free.

  8. #7
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    My 98 1.8T Variant has an aftermarket radio. It passed emissions no problem. That was about 2 months ago.

    I don't know if that helps you.

    Brett

  9. #8
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    My 98 1.8t AEB Variant won't scan unless the factory radio is installed.

  10. #9
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    I have the same problem. I also have the bad ABS controller, and I have a stock head unit. When Herman hooked up his Vag-COM we couldn't access anything except the ABS related stuff. I'm pretty sure it's the ABS, but I am getting my ABS rebuilt this week, so I can check to see if this fixes the problem.

  11. #10
    My pornstar name came up "Jay the Snork."
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    thanks for the extra input everyone.

    i felt up under the dash and the port seems to be seated securely. i haven't tried to look at it yet through the fuse panel opening. there is a chance i knocked something loose last year when i installed my column mount boost gauge, snakeing the hose through the dash.

    wheresjim- keep me up to date on your progress if you could, thanks.

  12. #11
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    If you have a bad ABS control unit it can cause communications problems with the scan tool. Try disconecting the control unit and see if you can communicate. This is a common problem with this car. If it is not and you have an after market radio check the aftermarket connectors there is a blue wire that is looped, cut the loop and it should allow you to communicate. The blue wire is looped from the electric anntenna signal and the K wire.

    David DeLeon, VW Master Technician

    Diamond Valley VW, Hemet CA

  13. #12
    My pornstar name came up "Jay the Snork."
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    what is a K wire?

  14. #13
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    Quote Originally Posted by mfitz
    what is a K wire?
    http://www.ross-tech.com/vag-com/aftermarket-radio.html
    Original Club B5 member: 08 R32 & missing my 99 B5

  15. #14
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    If you used a Metra wiring harness then the K-Wire is a non-issue. Metra doesn't even put a wire in the K-wire slot anymore because of this. Of course if your installer (or you if you did the install) is worth his ass he'll have properly connected the HUs power antenna lead to the powered antenna adapter and not the dash harness.

  16. #15
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    I had the same problem that you had. I ended up diconecting the aftermarket radio and took it to the smog test. It worked fine.
    Quote Originally Posted by mfitz
    My 98 1.8t is running great, no CELs, or any other issues that i know of (except one, i will get to that) but i had to take it in for annual smog testing. I went to two different places, but neither could get their diagnostic machine to get a reading on my car's computer.Any ideas why?

    My ABS controller is shot, but i can't believe that would interfere with a scan tool, would it? Or, is it possible that my OBD port is just busted/ disconnected somehow and needs to be replaced/repaired ? Has this happened to anybody else? I didn't see anything like this while searching the forums.
    I have 30 days to get this sorted out before i have to take my car back in for a retest, so the sooner the help the better. thanks in advance.

  17. #16
    My pornstar name came up "Jay the Snork."
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    Quote Originally Posted by quality_sound
    Of course if your installer (or you if you did the install) is worth his ass he'll have properly connected the HUs power antenna lead to the powered antenna adapter and not the dash harness.
    i seem to remember a second trip to Best Buy to get the powered antenna adapter, but that doesn't mean i hooked it up right

    i also already checked in the dash and didn't see any loose or disconnected wires.

    the plan now is to disconnect the radio and try again at the test center, and if that fails, disconnect the abs controller and try one last time.

    if none of that works, six of these might help. :biglaugh:

  18. #17
    My pornstar name came up "Jay the Snork."
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    Ahhhhhhhhh! great info.

  19. #18
    My pornstar name came up "Jay the Snork."
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    late update- removed aftermarket radio and the scan tool read my car just fine. thanks again to everybody for their help. I also identified the k-wire( there was a tag on it on the adapter harness saying "do not connect this wire on model year 95 and up VW's" ) and I clipped it, so hopefully i won't have to pull the radio every year.

    matt
    Last edited by mfitz; 07-31-2005 at 09:21 AM.

  20. #19
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    NO Reading

    Hi, I have the same problem. I get to reading.

    I have a bad ABS module and I have the original radio that come with the car, no work has been done under the dash board or near the fuse area. It fail the smog check because it could not read the computer. The tech reset all codes and drove it for 15 miles and returned to the same place, still it could not read the computer. Since I have the original stareo it should work, Now I have to check if any wires are loose and try again. and it not then I need to get the ABS module replace, incase this is the case.

    Any thoughts.

    Thank You

  21. #20
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    Quote Originally Posted by quality_sound
    If you used a Metra wiring harness then the K-Wire is a non-issue.
    Very true, however the older wiring harness adapters are typically the issue.

    When I bought my harness adapter in '98 it has the K-wire looped and I had to cut it because I had scanning issues.

    So, to correct Rusty (gasp), it is an issue on the 98's as well. :biglaugh:

    -Mark

  22. #21
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    VAG Can't connect any module

    Hello, I would like a help with my 99' passat AEB 1.8t tiptronic. I don't know if I'm in the right topic. After a heavy rain, my car had its floor flooded with water due to clogging of drains under the battery. I had to change the tiptronic gearbox module. For reasons of high cost, I bought used module and the car ran ok. VAG Connecting OK too, But 15 days later, dashboard turned on the ABS light with 3 beeps, intermittent, with increasing frequency until it lit constantly. At this time I only can connect VAG modules as engine, autotrans, etc except ABS when the ABS Module is unplugged. I sent it to a guy in Ebay located in California, (MODULE REPAIR PRO) who said he repaired the module but, surprise, I placed it in the car but the lights on dashboard but not turned off. How could I check for failures in the wiring harness or this have something with respect the replacing of tiptronic module? Or would test the repaired module with the multimeter?

  23. #22
    Moderate Moderator Steve in Chicago's Avatar
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    Your scan tool connects fine as long as the repaired ABS module is not connected? If that is the case, it appears the repaired module is the problem.

  24. #23
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    Yes, if I disconnect the abs module, VAG communicates. The problem is I have 02 modules and I find it unlikely that both are bad. Anyone know how can I test the abs module or my car wiring harness? Thank you very much!

  25. #24
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    To resurrect a tired old thread.

    Car: 2001 (before the 2001.5/B5.5 facelift) Passat wagon, AUG 1.8T, Tip

    Known problem: ABS module -- get STOP alternating with "service manual" or "brake manual," blinking BRAKE, solid ABS light, no CEL.

    VCDS communicates just fine, although understandably does not find ABS module on autoscan and reports no communication with ABS control under ECU scan. All 8 emissions test readiness codes come up "ready"/0.

    I took it to a local test-only smog station, and neither their freestanding unit nor their newer PC-based system can communicate with my car. I drove home, plugged in my VCDS, and had no problem communicating and scanning.

    Could/would the ABS be at fault? The owner of the test shop does not think so, and she claims she has smogged lots of cars with ABS lights on, but perhaps those were in earlier stages of failure. Should I try a different test station? I thought about things like loose or dirty OBD-II connector contacts, but I never have to fiddle or finesse anything to get my VCDS to talk communicate. Other suggestions?

  26. #25
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    New info -- I did get one bad VCDS scan, which indicated either "no DTC codes or no communication," even though it did find the engine control module. Unplugging the data/control port to the ABS control module returned me to my usual VCDS scan of "no communication from ABS."

    So ... lesson learned is to unplug your defective ABS module before going in for a smog test. Of course, if your state also requires a safety inspection, then you have to get the ABS repaired first.

  27. #26
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    Thanks for the update. So, did you pass smog with the ABS unplugged?

    With no tailpipe measurements of HC, CO, or NOx, do they give you any printout indicating what they found, or what they looked at (fuel trims, postcat MVBs)?

  28. #27
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    Quote Originally Posted by GLInick View Post
    Thanks for the update. So, did you pass smog with the ABS unplugged?

    With no tailpipe measurements of HC, CO, or NOx, do they give you any printout indicating what they found, or what they looked at (fuel trims, postcat MVBs)?
    I plan to go in Wednesday, this time with the ABS disconnected. Since they now do just an OBD-II scan, it should in principle be possible to use a VCDS to tell whether or not a car will pass smog -- I need to ask Uwe Ross and company about this.

    Here is my session log from the "no communication" run (bad ABS connected). If anyone gets one of these, I strongly recommend against trying for a smog test that day. Note that it skips over module 03, the ABS controller, but more importantly, it says possible communication error in the module 1 (ecu) test. It also fails to return a readiness code. I think this is our smoking gun for non-communication in a smog test -- perhaps someone more intimately familiar with the OBD-II bus protocol can confirm or deny this supposition.



    Chassis Type: 3B - VW Passat B5 (1997 > 2005)
    Scan: 01 02 03 08 15 16 17 19 35 36 37 46 47 55 56 57 58 75 76 77


    Mileage: 94450km-58688miles
    -------------------------------------------------------------------------------
    Address 01: Engine Labels: 06B-906-018-AUG.clb
    Part No: 4B0 906 018 BQ
    Component: 1.8L R4/5VT G 0003
    Coding: 16551
    Shop #: WSC 30856
    VCID: 71E96CF13B0493A9905-5122

    No Faults Found
    or DTCs not supported by controller
    or a communication error occurred

    -------------------------------------------------------------------------------
    Address 02: Auto Trans Labels: 01V-927-156.lbl
    Part No: 3B0 927 156 AA
    Component: AG5 01V 1.8l5VT USA 1010
    Coding: 00104
    Shop #: WSC 00000
    VCID: 65C108A1FFCC4F09FCD-5140

    No fault code found.

    -------------------------------------------------------------------------------
    Address 15: Airbags Labels: 6Q0-909-605-VW5.lbl
    Part No: 6Q0 909 605 C
    Component: 03 AIRBAG VW6 0003
    Coding: 12339
    Shop #: WSC 05311
    VCID: 377D92E915E00D999E1-4AE8

    No fault code found.

  29. #28
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    Compare with that same ABS disconnected -- good-to-go readiness 0000 0000, no "communication error occurred" message:

    Chassis Type: 3B - VW Passat B5 (1997 > 2005)
    Scan: 01 02 03 08 15 16 17 19 35 36 37 46 47 55 56 57 58 75 76 77


    -------------------------------------------------------------------------------
    Address 01: Engine Labels: 06B-906-018-AUG.clb
    Part No: 4B0 906 018 BQ
    Component: 1.8L R4/5VT G 0003
    Coding: 16551
    Shop #: WSC 30856
    VCID: 71E96CF13B0493A9905-5122

    1 Fault Found:
    18057 - Powertrain Data Bus
    P1649 - 35-00 - Missing Message from ABS Controller
    Readiness: 0000 0000

    -------------------------------------------------------------------------------
    Address 02: Auto Trans Labels: 01V-927-156.lbl ...

  30. #29
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    Update -- a second unit from eBay seems to solve the problem. I cleared just the ABS module error code, the ECU still shows full smog test ready 0000 0000, and the various ABS warning messages and lights no longer come on.

    By the way, on a B5 (not 5.5 -- YMMV), one can pull the wheel well liner without jacking the car or removing the front wheel. 11 T20 bolts, a little wiggle and finesse, and the liner is out. Three 10mm bolts and the windscreen washer reservoir bottle drops out, unhooking the pump and spilling water all over the garage floor. Unplug the two ABS control electrical harnesses, and one now has a clean shot at all 6 T20 bolts which hold the ABS brain to the hydraulics.

  31. #30
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    Ok. I hope someone can help me. Ive looked through a lot of post and haven't seen my specific issue. If you have then please point me in the right direction.. Ive had an aftermarket radio ever since I got my car 00' b5 wagon. Ive never had a problem scanning my dlc. some dick recently stole my radio so I got another one and ever since I haven't been able to scan my car. Always says no link. Kwire isn't hooked up. Ive checked it for voltage and everything seems to be fine so Im almost for sure its not that. im gonna ghost ride this car off of a cliff if I cant figure out the problem. Please help!!!

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