Fault code 2090: Diagnosis/troubleshooting

NOTE:

Before replacing the control module, the ground connections, power supply and plug connections on the control module must be checked.
When replacing the vehicle electrical system control module, observe the coding of the control module.
After the test drive, read out the fault memory with the Porsche System Tester II No. 9588 again. Additional causes of faults that could damage the vehicle electrical system control module should be detected and remedied.

DIAGNOSIS/TROUBLESHOOTING CHART

Work instruction			Display OK	If not OK
1	Carry out actuator test using Porsche System Tester II No. 9588.		Headlight washer functioning error See FAULT CODE 0924 → End Rain/light sensor functioning error Go to Step 2
2	Check lines for short circuit to B+:	Switch off the ignition. Pull out plug 'L' on vehicle electrical system control module: Remove rain/light sensor plug. Switch on ignition. Measure voltage between vehicle electric system plug 'L' 'Pin 3' and ground.	< 0.3 V Go to Step 3	Repair / replace wiring harness → End
3	Check line for short circuit to ground:	Switch off the ignition. Measure resistance between vehicle electric system plug 'L' 'Pin 3' and ground.	∞ Ω Go to Step 4	Repair / replace wiring harness → End
4	Check line for open circuit:	Measure resistance between vehicle electric system plug 'L' 'Pin 3' and rain/light sensor plug 'Pin 1'.	< 5 Ω Go to Step 5	Repair / replace wiring harness → End
5	Check rain/light sensor ground line:	Measure resistance between rain/light sensor plug 'Pin 2' and ground.	< 5 Ω Go to Step 6	Repair / replace wiring harness → End
6	As an experiment, replace rain/light sensor, then: Erase fault memory. Satisfy diagnostic conditions Read out fault memory again		Fault code 2090 not entered. → End	Fault code re-entered. Go to Step 7
7	Replace vehicle electrical system control module Observe note		→ End