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Discussion Starter #1
Dear members,

Car is a Alpina B5S (E60 2008/10) with 103.000 km on it. Car came in with the following symptons:

- when driving suddenly a few errors come up on the dash
- the gearbox lever can not be changed, gearbox remains in 4th gear and no reverse selecting is possible
- radio/nax goes out, clima goes off
- power steering goes off
- ABS/DSC goes off (light illuminate)

Checked error memoery and its full of error codes related to not enough battery voltage

Monitored the system voltage after start and the voltage remains equal (~11.5-12V). When the car is driven the charge changed sporadic, if i play with the throtlle the voltage comes up/down.

I checked alternator control PWM from DME when engine is started and this one is also fluctuating. Strangest thing is, it sometimes remain 0% when the engine is started and the voltage is near 10.5-11.5 V. I would expect 100% due to the low voltage or am I wrong?

I know that the pulley on the crankshaft that drives the (alternator,waterpump, power steering (also comes up as an error) can get damaged on M57DXX engines but does anybody encounters the same on these V8 engines?

I think the pulley, alternator or engine control unit might be defective.
- pulley since the same symtons happended on 2 530d/525d before in the workshop. Also when changing the engine speed quickly with the accelerator pedal the voltage charge becomes far from consistent which may be caused by slipping belt/pulley.
- alternator and ECU; although the engine ecu controls the alternator charge and reads out the correct voltage during live data I have a slight suspicion it might not function properly.

If anyone knows or has recommendations please mention.

BR,
Tomba
 

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Discussion Starter #4
Removed the alternator and tested it at a revision shop for alternators. Alternator is broken and replaced. Car is functionating OK.
To remove the alternator the supercharger and supporting bracket needs to be removed.
 
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