12 31 009 Checking alternator (BSD)
WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 2008 BMW Z4, 2008 BMW 328xi, 2008 BMW 328i, 2008 BMW 323i, and 2007 BMW Z4. However, it is still accessible from the selected car via links, so may be relevant.
Necessary preliminary tasks:
- Correct connections on charged battery
- Correct connections on alternator and starter motor
- Good ground connection between engine and body
- Tensioned ribbed V-belt
- Read out DME/DDE fault memory.
NOTE:
The alternator with BSD interface can communicate with the engine control unit (DME/DDE).
The alternator is not connected to the charge telltale light.
The alternator can identify various faults.
BSD alternator can be recognized by the plug connection on the alternator.
Connect diagnosis tester.
- Function selection
- Complete vehicle
- Drive
- Voltage and current regulation
- Voltage and current generation
- Alternator
- Follow instruction in diagnostic program
Oscillogram for a fault-free alternator:
Oscillogram for a faulty alternator:
One phase interrupted.
Repair/exchange alternator.
Inter turn fault.
Repair/exchange alternator.
Open circuit in negative diode.
Repair/exchange alternator.
Short circuit in positive diode.
Repair/exchange alternator.
Open circuit in positive diode.
Repair/exchange alternator.
Open circuit in exciter diode.
Repair/exchange alternator.
Assemble engine.
Check function of DME/DDE.