Fuse and relay module function - GF07.13-P-3141-02HA

Fig 1: Identifying Fuse And Relay Module Function

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Function with ignition "ON" and engine running 

Turning the ignition ON energizes the fuse and relay module (K40/4) and the engine control module. Relay K3 supplies battery voltage (unfused) via fuse 3 to the engine control module. Power is supplied to the remaining IFI [ERE], DFI [EVE] and CDI system components via fuse 2.

Function with ignition "OFF" 

Turning the ignition OFF stops actuation, though the holding relay circuit in the engine control module continues to supply power to the fuse and relay module (K40/4) for approximately 4 seconds via socket B1.3. The engine control module detects the voltage drop at circuit 15 and initiates engine shutdown.