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Thread: Computer - replacement of repair?

  1. #1
    Join Date
    Jan 2020
    My Cars
    2003 E85 z4 convertible

    Computer - replacement of repair?

    Several people have troubleshot my problem and all have been unsuccessful. Basically the car won't start; turns over, has great fuel pressure and no firing of the fuel injectors. Lots of other OK things like battery, fuses, etc. Latest analysis indicates no output from the DME - I call this the COMPUTER. Wires look good, connections appear ok. The OBDII scan tool that I use (BLUEDRIVER) said P1634. I canceled the previous fault code which stated that the cranksensor was bad by actually putting in a new sensor. Code then disappeared but still no start. P1634 still remained. Car was towed and shop went to work diagnosing the problem using the BMW approved diagnosing tools They got a crank sensor fault. I told them I replaced it but they recommended getting a new one so they did. Still no start. No firing of the fuel injection/sparkplug doodoos.
    Here's the big choice now - troubleshoot the existing computer at a shop, fix and reinstall - ??$450-850?? - or buy new at $1645 plus install?

    ANYONE have such a choice/experience in the past? Not concentrating on cost so much as on the reliability of the repair vs. new DME, etc.

  2. #2
    Join Date
    Oct 2003
    My Cars
    99 M3
    Can a second hand DME be coded to the car/EWS?

    Sent from my iPhone using Tapatalk

  3. #3
    Join Date
    Jan 2015
    Timaru, New Zealand
    My Cars
    Two Z3 Roadsters 2L & 3L
    P1634, 115 (dec), Throttle Valve Adaptions Spring test failed. When ever you go to start the engine, The DME will test the throttle body. There will be a little flip of the butterfly. If the throttle body test fails, you will get this code. Remove the rubber boots from the throttle body and watch the butterfly when you go to start the car. Does the butterfly flip? If it does not flip, try resetting the throttle body adaptions.

    When you say the there is "no output from the DME", what output is not working? Be specific and state the connector and pin number and what it is operating e.g. X60002 pin 23 DME relay .

    Do you have spark when cranking? If you do not have spark, check for voltage at Fuse 01. Fuse 01 is powered by the DME relay K6300. If K6300 is not being energised by the DME then the "Drive Away" protection is stopping the engine start.

    The Car's engine security system (EWS) has two parts:
    1) Crank protection. The key that is put into the ignition has to be recognised by the EWS. When this occurs, the EWS enables crank (which you have) and sends an ISN signal to the DME.
    2) Drive away protection. The DME has to recognise the ISN signal. If its good it energises the DME relay K6300 and allows spark to occur, so the engine will start.

    If you have no spark during starting, then you need to align the ISN between the EWS and the DME.
    Last edited by Muzz258; 11-09-2020 at 06:28 PM.
    2000 2.0L Z3 Roadster, Mora Red, Individual, Originally from UK, daily drive.
    2000 3.0L Z3 Roadster, Siena Red, BMW Development car, Originally from Germany, Garage Queen
    2000 323i E46
    There is only one thing more pleasurable than working on a Z3, that's driving it top down on a fine day.

  4. #4
    Join Date
    Jan 2008
    Arida Zona
    My Cars
    If you can read codes you have communication with DME

    Cars will crank and not start if you have a bad crankshaft sensor

    A good shop would have checked wiring already. The next step is to do just that... Check for continuity between sensor and DME

  5. #5
    Join Date
    Oct 2010
    Miamisburg, Ohio
    My Cars
    1997 BMW 328iC
    If needed I have used these guys to rebuild the computer in my sons car. They had a lifetime warrantee.

  6. #6
    Join Date
    Jan 2016
    My Cars
    2001 525it
    And who has tried to diagnose this problem

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