Fault code 18: Diagnosis/troubleshooting

DIAGNOSIS/TROUBLESHOOTING (FAULT CODE 18)

Work instruction			Display OK	If not OK
1	Check the wire from the alarm system control module to the switch for power windows for short to ground.	Switch off ignition Pull plug A off the alarm system control module Pull plug off switch for sliding roof Pull plug off switch for power windows Measure resistance between plug A on alarm system control module pin 18 and ground	Step 2	Repair wiring harness -> End
2	Check the wire from the alarm system control module to the switch for power windows for open circuit	Measure resistance between plug A on the alarm system control module pin 18 and plug pin 4 on the switch for power windows	< 5 Step 3	Repair wiring harness -> End
3	Check wiring from the switch for power windows to the power window motors on the right and left for short circuit to ground	Pull plug off the power window motor on the right and left Measure resistance between pin 1 of each switch for power windows and ground Measure resistance between pin 2 of each switch for power windows and ground	Step 4	Repair wiring harness -> End
4	Check wiring from the switch for power windows to the power window motors on the right and left for short circuit to ground	Measure resistance between pin 1 of each switch for power windows and pin 4 of each plug on power window motors Measure resistance between pin 2 of each switch for power windows and pin 3 of plug on power window motors	< 5 Step 5	Repair wiring harness -> End
5	Detect faulty component	Push plug on switch for sliding roof again Connect special tools 9616 and 9617 Measure voltage at special tool 9616, pin 18 and ground	> 11 V Step 6	Check switch for the sliding roof or wiring to the drive unit for the sliding roof -> End
6	Detect faulty component	Push plug on left power window motor again Push plug on switch for left power window again Actuate switch for left power window and simultaneously measure the voltage between special tool 9616, pin 18 and ground	> 11 V Step 7	Step 8
7	Detect faulty component	Push plug on right power window motor again Push plug on switch for right power window again Actuate switch for right power window and simultaneously measure the voltage between special tool 9616, pin 18 and ground	> 11 V -> End	Step 9
8	Replace left power window motor		-> End
9	Replace right power window motor		-> End