This bulletin applies to 2013 BMW 528i models. An “increased battery discharge” message may appear in the central information display (CID) upon engine startup. In some cases, the message “battery charge level low” may also appear. In most cases, a fault code is not set for the intelligent battery sensor (IBS).
A software error in the IBS causes an incorrect state of charge (SoC) to be stored in the DME. The power management system then interprets this as a heavily discharged battery and informs the customer via a check control message. In reality, the battery does not have a problem.
1. Diagnose the vehicle using ISTA 3.39 or later and complete the “energy diagnosis” test plan. Always connect a BMW approved battery charger/power supply.
2. If “IBS faulty” is listed in the results of the energy diagnosis test module screen, follow test module recommendation and replace the IBS sensor with the improved IBS battery negative cable P/N 61 21 9 302 358.
3. If “IBS faulty” is not listed on the test module screen, diagnose all other most likely causes as listed in the test module until the energy diagnosis test plan is completed.
The revised energy test module reads out the following data from the vehicle and determines if the IBS needs to be replaced:
- IBS software version is too low (automatically determined by the test plan).
- One of the six (one current and five days prior) SoC values is less than 10%.
- The other five SoC values are greater than 70%.