P0686

P0686

Diagnosis information - Control unit DME (DFI)

Main relay off

Diagnostic conditions
- Vehicle voltage > 8.0 V
- Ignition off
- Control unit run-on completed (See [Information])
- then Ignition on

Possible fault causes
- Main relay Faulty (Contact stuck)
- Short circuit to B+ Lead between Main relay and Control unit DME (DFI) (Power supply Control unit DME (DFI))
- Short circuit to ground Lead between Control unit DME (DFI) and Main relay (Activation Main relay)

Fault setting condition(s)
- Power supply Control unit DME (DFI) > 4.0 V to connector [A] contact 3/5/6, at:
- Power supply Control unit DME (DFI) 0.0 V to connector [A] contact 34 (Terminal 15)

INFORMATION
- After the ignition is switched off (terminal 15), the DME control unit switches to control unit after-run mode.
- The run-on period depends on many boundary conditions (e.g. engine temperature for fan operation).
The run-on duration can be 1 minute when the engine is cold and up to 45 minutes when the engine is hot.