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

WARNING: This page is about a different car, the 2005 BMW Z4, 2004 BMW Z4, and 2003 BMW Z4. However, it is still accessible from the selected car via links, so may be relevant.

Necessary preliminary tasks:

Check stored fault messages.
Switch off ignition.
Observe Instructions For Disconnecting And Connecting Battery .
Disconnect battery ground wire and mask it.
Remove suction filter housing .
Remove Alternator Drive Belt .

Unlock and detach plug connection (1).

Release nut (2) and remove battery positive lead.

Tightening torque, see 12 31 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Fig 1: Removing Battery Positive Lead

Courtesy of BMW OF NORTH AMERICA, INC.

Remove cover from idler pulley (1).

Release screw and remove idler pulley (1).

Release screw and remove alternator (2).

Fig 2: Removing Alternator

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Turning lock of tensioning roller must engage in alternator groove.

Fig 3: Identifying Tensioning Roller Lock Position

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Read out fault memory of DME control unit.

Now clear the fault memory.