Fault code 1737: 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 ...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: 'Implausible signal' → The fault is detected if the resistance between plug B, pins 4 and 5 remains unchanged for more than 1.5 seconds during memory activation.

WORK INSTRUCTION CHART

Work instruction			Display OK	If not OK
1	Check operation of adjustment motor for passenger's door mirror	Change vertical position of passenger's door mirror using mirror adjustment switch.	Go to step 2	=> Check for fault code 940.
2	Check vertical potentiometer in passenger's door mirror adjustment motor	Switch off ignition. Remove adjustment motor for passenger's door mirror. Pull plug off door mirror adjustment motor. Measure resistance between pin 1 and pin 7 on adjustment motor socket. Measure resistance between pin 5 and pin 7 on adjustment motor socket. Move adjustment motor by hand from stop to stop in vertical direction.	Change in resistance of vertical potentiometer. 300 - 1,100 Ω Go to step 3	Go to step 7
3	Check power supply of vertical potentiometer to door mirror adjustment motor	Switch on ignition. Measure voltage on adjustment motor plug between pin 1 and pin 5.	Approx. 12 V Go to step 6	Go to step 4
4	Check wiring for short circuit to B+	Switch off ignition. Pull off plug B on passenger's door control module. Measure voltage on adjustment motor plug between pin 1 and ground.	< 0.3 V Go to step 5	Repair wiring. → End
		Measure voltage between adjustment motor plug, pin 5 and ground.
		Measure voltage between adjustment motor plug, pin 7 and ground.
5	Check wiring for short circuit to ground	Measure voltage on adjustment motor plug between pin 1 and battery positive connection.	< 0.3 V Go to step 6	Repair wiring. → End
		Measure voltage between adjustment motor plug, pin 5 and battery positive connection.
		Measure voltage between adjustment motor plug, pin 7 and battery positive connection.
6	Check wiring for open circuit	Switch off ignition. Measure resistance between pin 4 of control module plug B and pin 1 of adjustment motor plug.	< 5 Ω Go to step 8	Repair wiring. → End
		Measure resistance between pin 7 of control module plug B and pin 5 of adjustment motor plug.
		Measure resistance between pin 13 of control module plug B and pin 7 of adjustment motor plug.
7	Replace passenger's adjustment motor		→ End
8	Replace passenger's door control module		→ End