P1688

P1688

Diagnosis information - DME (DFI)

Engine compartment purge fan driver LOW

NOTE:
The control line is monitored from the DME control unit to the relay for engine compartment purge fan level LOW.
The switch-on conditions depend on the following temperatures:
- Engine compartment
- Ambient air

They vary depending on vehicle type, model year, engine variant, etc. (see [Function description]).

Diagnostic conditions
- Supply voltage > 7 V
- Engine start recognized
- Engine cover closed (911 only)

Possible fault causes
- Short circuit to B+/ground/between lines or open circuit in the control line to the relay for engine compartment purge fan LOW
- Open circuit in the power supply to the relay for engine compartment purge fan LOW
- Relay for engine compartment purge fan LOW faulty
- DME control unit faulty