Preconditions

Preconditions:

- First, read and understand SIB # 61 08 00
- Charge the vehicle battery with a BMW recommended (Deutronic) battery charger to obtain a minimum of 12.6 Volts. The battery charger must be disconnected prior to any draw testing.
- Vehicle charging system must be operating correctly.
- Check for faults and correct any faults that are present.
- Have a copy of the bus chart ready for reference. Understand the basics in order to "Divide and Conquer" the bus network.
- Review the power supply wiring diagram to understand the three (3) separate routes that the B+ potential can travel. The B+ lead that feeds the IVM/ECM, starter and generator. This lead has a junction in the luggage compartment and supplies the aluminum ribbon cable to the front of the vehicle.
The second is the feed from the Power Module 30 B to the front fuse panel in the glove box. Moving the current probe to each individual cable will isolate which circuit has the current draw(s).
- Review the Vehicle Sleep Mode shut down protocol chart to assist with comparisons when diagnosing a faulted vehicle.

Please Review the Following General Observations:
1. After switching the ignition "OFF", the CAS light remains "ON" for approximately 2 minutes. When the CAS LED goes out, this indicates that the Bus network is sleeping. At this time the current measurement should not be > 800 mA (.8 A).
2. After approximately 16 minutes the CAS led illuminates for approximately 30 seconds (Bus network is awake). After the CAS LED goes out (Bus network is sleeping), the BZM seat switch lights (left and right) will turn off. At this time the Power Module circuit VA-D roof consumers shut down (hint - leave a map light on as a visual). The current draw is approximately 200 mA (.2 A) at this time.
3. The remaining time until the vehicle is in "sleep mode" will occur in approximately 44 minutes (vehicle dependent). The total time for sleep mode could take up to 70 minutes.
4. The final closed circuit current draw should be approximately 30 mA (.030 A) or less (normal peaks last for approx. 20 seconds each). These normal peaks are a result of the Instrument Cluster performing a temperature status check (diminishes in frequency as time goes on).
5. Always allow the vehicle to go into the sleep mode naturally. Do not use the DISplus/GT1 test module to expedite shut down on the initial diagnosis. This test module can be used after the conformation of failure has occurred and additional testing is required. This will help in speeding up the subsequent diagnosis.