Fault Code 0121

Fault code 0121

Passenger's door warning and exit lights

NOTE: This fault was detected by the 'passenger's door' control module.

Diagnostic conditions
- Ignition on
- Battery voltage OK (11.4 to 14.5 V)
- Internal function test on passenger's door control module
- Open/close door

Possible causes of fault
- Wiring faulty
- Lights faulty

Affected pins
Passenger's door control module, plug A:
- Pin 1 'terminal 31'
- Pin 16 'door exit light'
- Pin 32 'warning light'

Diagnosis/troubleshooting

NOTE:
Visual inspection: In the next troubleshooting section, please check first that the affected pins on the passenger's door control module plug connection are neither damaged nor corroded. The wiring and plugs of the affected components must also be checked for external damage and correct contacts. Repair damaged or corroded pins if possible, otherwise replace affected pins. Repair or replace damaged wires.

NOTE:
Sporadic faults: In the event of faults that occur sporadically, the wiring positions that are linked to moving parts on and in the vehicle must be checked for each system. Various statuses that can cause faults must be simulated with the help of the wiring diagram.

NOTE:
Battery voltage: A battery voltage of between 11.4 and 14.5 V is required for the following troubleshooting procedure. This must be checked and provided, if necessary. On the vehicle electrical system, the voltage to the fuse (input side) must be guaranteed.

NOTE: The door warning light and the door exit light are activated together on opening and closing the door. The voltage supply, however, is split on two separate pins.