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2004 BMW 745Li Question: Is this a transmission or computer programming problem.

 

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cutman, Fredericksburg, VA, November 30, 2010, 10:40
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When the vehicle down shift to a lower gear (ie. 2 to 1) it makes a hard shift or clunking sound. Is this a transmission or computer programming problem.

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    November 30, 2010, 11:56
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     Master

    Could be both, could be even external to the transmission, like a sensor.
    Is the Check Engine Light on? If the EGS (transmision controller) won't receive a necessary signal, like a Mass Air Flow signal, it could do this.
    You really need to get it diagnosed by a BMW specialty shop to see what causing the problems. They should be able to pull out diagnostic trouble codes from the affected modules and be able to estimate the parts and repair cost for you.

    Zee

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    cutman, November 30, 2010, 14:09
     Rookie

    Thanks Zee Tech. The Check Engine Light is not on. Do u think that the transmission has to b replace in order for this problem to b solved (hope not).

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    ZeeTech, November 30, 2010, 14:20
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     Master

    It's hard to tell without diagnostics. There could be many different things - not directly connected to the transmission- cause shifting problem. As I said, even a bad MAF signal could cause this and the CEL might be not on for air flow problem, but there could be a DTC in the EGS for torque calculation. So it could be a sensor problem with no CEL and bad shifting, with a perfectly good transmission. That's why the diagnostic is necessary. You don't want to replace a very expensive part if the problem is somewhere else.
    Let's hope it's not the transmission. Do you know a good independent BMW shop in your area?

    Zee

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    cutman, November 30, 2010, 14:37
     Rookie

    I took the vehicle to an Independent Dealer, they did a computer diagnostics and stated that the transmission fuel pressure was low (2.8 instead of the required Number). Do you think the MAF has something to do with this?

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    ZeeTech, November 30, 2010, 14:56
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     Master

    I think they meant : line pressure. Anyway here is the TSB for the software issue.
    Make sure you have the latest software in the EGS, as you can see software fault could also cause this problem.

    A/T - Harsh 3-2/2-1 Downshifts/Clunk Noise

    SI B 24 17 07
    Automatic Transmission

    December 2007
    Technical Service

    This Service Information bulletin supersedes SI B24 17 07 dated July 2007.
    designates changes to this revision

    SUBJECT
    Harsh 3-2 and/or 2-1 Downshifts

    MODEL
    E65 and E66 (7 Series) 745i and 745Li with N62 and GA6HP26Z transmission

    Vehicles from SOP up to 03/2005
    SITUATION
    IMPORTANT :

    Depending on the production date of the vehicle, there are different situations and corrective measures that must be carefully followed. Running production changes in vehicle hardware and software divide these situations into three distinct production periods.
    A. For vehicles produced from SOP up to and including 02/2003:

    ^ A harsh 3-2 and/or 2-1 downshift when slowing to a stop

    ^ A harsh downshift when accelerating at highway speeds

    ^ A "clunk" noise during a 2-1 downshift while driving slowly to a rolling stop, or during a load reversal as described in SI B24 14 07 and SI B26 01 06.

    B. For vehicles produced from 03/2003 up to and including 08/2003:

    ^ A "clunk" noise during a 2-1 downshift while driving slowly to a rolling stop, or during a load reversal as described in SI B24 14 07 and SI B26 01 06.

    C. For vehicles produced from 09/2003 up to and including 02/2005:

    ^ A harsh 3-2 downshift when slowing to a stop

    ^ A "clunk" noise during a 2-1 downshift while driving slowly to a rolling stop, or during a load reversal as described in SI B24 14 07 and SI B26 01 06.

    CAUSES
    EGS software calibration

    Driveshaft guibo coupling deterioration for "clunk" noise complaint
    CORRECTION
    For Situation A: Harsh downshift complaints

    1. Verify that the transmission fluid level is correct.

    2. Perform a "Short test" and correct all Drivetrain-related faults first.

    3. [NEW] If the vehicle integration level (vehicle data status) is E065-07-03-800 or less, reprogram the vehicle using the latest version of Progman to E065-07-09-800 or higher.

    4. Clear the EGS adaptations after programming is completed.

    5. If after reprogramming, harsh downshifts are still felt, submit a regular PuMA case entitled "ZF shift quality". To be processed, the case must include ALL information listed in SI B24 23 07.

    For "clunk" noise complaints in vehicles produced from 10/2002 up to and including 02/2003, inspect the driveshaft guibo coupling for deterioration or separation as described in SI B24 14 07.

    For Situation B: "Clunk" noise complaints
    1. Verify the complaint.

    On vehicles produced from 03/2003 up to and including 08/2003, the only repair is to inspect the driveshaft guibo coupling for deterioration or separation as described in SI B24 14 07.
    Note :There are no further EGS software changes for vehicles in this production period.

    For Situation C: Harsh 3-2 downshift complaints
    1. Verify that the transmission fluid level is correct.

    2. Perform a "Short test" and correct all Drivetrain-related faults first.

    3. Submit a Puma case entitled "Urban Program" to obtain the access code needed to complete the retrofit reprogramming of the EGS module.

    4. Start a programming session using the latest version of Progman and select "Urban Program" from the retrofit options menu. The measures plan should indicate a higher programmed number and an EGS calibration change.

    5. Clear the EGS adaptations after the programming is completed.

    For "clunk" noise complaints in vehicles produced from 09/2003 up to and including 02/2005, inspect the driveshaft guibo coupling for deterioration or separation as described in SI B24 14 07.
    WARRANTY INFORMATION
    Covered under the terms of the BMW New Vehicle Limited Warranty.

    Please refer to the latest KSD for all applicable labor operations and allowances.

    If the appropriate labor operation is not contained in KSD, then a work time labor operation should be used.

    Defect Code 24 00 39 61 00

    Zee

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