Fault Code 2090

Fault code 2090

Headlight cleaning system relay/rain and light sensor supply

Diagnostic conditions
- Ignition on
- Internal vehicle electrical system control module function test
- Headlight cleaning system and driving light assistant are coded
- Output on the control module is active and the fault must occur at least three times before it is stored in the fault memory
- Drive link test

Possible causes of fault
- 'open circuit/short circuit to B+'

The following components are arranged and monitored in two groups in the vehicle electrical system control module:

Group 1
- 'Control lamp warning light'
- 'Headlight cleaning system relay'
- 'Battery charging relay'

Group 2
- 'Level control function command'
- 'Rain/light sensor supply'

A fault can only be allocated uniquely to group '1' or '2' if there is a 'short circuit to ground'.

The fault type 'open circuit/short circuit to B+' can only be allocated uniquely when there is active output. If there are at least two active outputs, the fault code is assigned to both groups. The exact allocation of the fault can only be determined using the drive link test.

Affected pins
Plug 'J' on vehicle electrical system control module:
- Pin 11 'output to headlight cleaning system relay'

Plug 'L' on vehicle electrical system control module:
- Pin 3 'input from power supply for driving light assistant/rain and light sensor'

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.