Vehicle Electrical System (BNSG)
Fault code 1704Terminal 58d (instrument lighting dimming)
NOTE: This fault can also be caused by a faulty fuse. Given this, it is advisable to check the fuse first before starting to check the wiring and components.
Diagnostic conditions
- Ignition on
- Instrument lighting on
- Instrument lighting brightness set to 'Maximum' either manually or via drive link test
Possible causes of fault
- 'Fuse faulty'
- 'Short circuit to ground' Failure of instrument lighting brightness control.
Affected pins
Plug 'J' on vehicle electrical system control module:
- Pin 1 'terminal 58d power supply output of potentiometer for setting instrument lighting'
- Pin 3 'terminal 58d ground output of potentiometer for setting instrument lighting'
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.
