12 63 520 Replacing main relay (M54 / S54)

WARNING: This page is about a different car, the 2002 BMW M Roadster, 2002 BMW M Coupe, 2001 BMW M Roadster, and 2001 BMW M Coupe. However, it is still accessible from the selected car via links, so may be relevant.

Switch off ignition.

Connect DIS Tester.

Release screw connection of electronics box (1).

Fig 1: Removing Electronics Box

Courtesy of BMW OF NORTH AMERICA, INC.

Installation :

Tightening torque, 12 14 4AZ. Refer to 12 14 ELECTRONIC SHIFT UNITS OR CONTROL UNITS .

Remove electronics box (1).

Arrangement:

Fig 2: Locating Main Relay And Fuses

Courtesy of BMW OF NORTH AMERICA, INC.

Notes on troubleshooting :

If the starter motor cranks the engine during the starting sequence but the engine fails to fire, then:

Check engine fuses
If fuses are blown, replace them completely with fuse holder
Find out why fuses have blown
Continue troubleshooting as per DIS instructions.