Electrical - MMI Shows Inaccurate Battery Charge State
27 MMI displays inaccurate battery charge state27 09 03
2016847/5
June 26, 2009.
Supersedes Technical Service Bulletin Group 27 number 09-01 dated January 15, 2009 for reasons listed below.
Affected Vehicles
Condition
REVISION HISTORY
^ The message Battery weak appears in the driver information system.
^ A battery level of 10% is displayed in the MMI Car menu.
Technical Background
Battery is actually discharged due to a closed-circuit current problem or software fault present in the battery energy manager (BEM).
Production Solution
Software change of the BEM to version 0490 (Audi A6) or 0510 (Audi A8).
Service
1. Use a Midtronics tester on the battery posts to check whether the battery is discharged.
2. If the battery is discharged and you will need to open a TACS ticket, you will need to provide the following information online to the TAC:
^ The vehicle repair history.
^ Measured value blocks 1-7 of the energy manager.
^ The manufacturer and capacity of the battery.
The vehicle battery history can be found as follows: Select Guided Fault Finding or Guided functions >> Function >> Component selection/Body (repair group 01; 27; 50 - 97)/Electric system (repair group 01; 27; 90 - 97)/01 >> Self diagnosis systems/61 >> battery control/J644 >> control unit for energy management, Functions/J644 and read vehicle history (repair group 27). Store this information on a USB device.
3. The SW level may need to be updated regardless of whether the battery was discharged. Determine the SW level of the BEM.
4. BEM SW up to Version 240 cannot be updated and does not need to be updated, as both the hardware and the software work correctly. Proceed to step 7.
5. If the SW Version of the BEM is between 270 and 490, a SW update will be necessary. Insert a USB memory stick into the VAS 505X tester to capture the diagnostic log electronically. Then:
^ For A6 models: Update online via software version management (SVM). Use action code C6BEM01. If it is not possible to update online via SVM, use Update CD 4F0 906 961 K.
^ For A8 models:
^ For MY 2005 and above, update online via SVM. Use action code D3BEM01.
^ For MY before 2005, use Update CD 4E0 906 961 G.
6. Check whether the condition has been resolved.
7. If the condition persists, check whether a closed-circuit current issue is present (load condition in the measured value block 6, closed-circuit current history in the history data block 02xx of the BEM).
8. If you find a closed-circuit current issue, determine the causal part and replace it.
Replacement of the BEM is not permitted and will be debited.
Warranty
In case of a closed-circuit current issue, code the claim according to the causal part.
In cases where a BEM software update is necessary:
Required Parts and Tools
Replacement of the Battery Energy Manager is not permitted and will be denied.
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.