P0441

P0441

Diagnosis information - DME V8 DFI

NOTE: In the case of the Turbo, the tank vent line feeds into both the connection piece of the positive crankcase ventilation as well as into a hose which is routed to the intake side of the turbocharger.

NOTE:
- Diagnosis of the tank vent valve takes place 1 x per journey.
- The tank vent valve is detected as OK if the load factor of the carbon canister is > 0.7. This value guarantees that the load factor has been re-taught. This is possible only if the tank vent valve is OK.
- If the load factor of the carbon canister is < 0.7, various engine variables are evaluated when the tank vent valve opens. These must change correspondingly if the valve opens correctly. These engine variables include, for example:
- Engine speed
- Idle control
- Released throttle valve area
- Lambda control
- Manifold pressure

Diagnostic conditions
- Vehicle voltage > 9 V
- Time after engine starts > 2 minutes
- Engine idling > 5 seconds
- Engine temperature > 40 °C (104 °F)
- Ambient temperature > 4 °C (39 °F)
- Ambient air pressure > 730 hPa
- Vehicle standstill (vehicle speed = 0 km/h)
- Transmission range P or N, or no gear selected.
- Steering wheel straight
- Air conditioning switched off
- All loads switched off
- All oxygen sensors ready for operation
- No oxygen sensor fault stored
- No tank vent driver fault stored

Possible fault causes
- Tank vent valve faulty (remains stuck in an open or closed position)
- Tank vent valve installed back to front
- Line between carbon canister and tank vent valve has leak, is trapped or is blocked
- Purge-air lines between tank vent valve and intake manifold have leak or are trapped or blocked (in the Turbo via a T-piece also on the intake side of the turbocharger)