Alternator: Service and Repair

12 31 020 - Removing and installing or replacing alternator (M54)





Necessary preliminary tasks:
- Check stored fault messages.
- Switch off ignition.
- Observe instructions for disconnecting and connecting Instructions for Disconnecting and Connecting Battery battery.
- Disconnect battery ground wire and mask it.
- Remove suction filter housing Service and Repair.
- Remove alternator drive belt Replacing Alternator Drive Belt (M52/S52/M52TU/M54/M56).





Unlock and detach plug connection (1).
Release nut (2) and remove battery positive lead.
Tightening torque 12 31 1AZ [1][2]Specifications.





Remove cover from idler pulley (1).
Release screw and remove idler pulley (1).
Release screw and remove alternator (2).





Installation:
Turning lock of tensioning roller must engage in alternator groove.





Note:
Read out fault memory of DME control unit.
Now clear the fault memory.