P0441

P0441

Fuel tank ventilation system above/below limit value

NOTE:
- Diagnosis of the tank vent's permeability is performed by evaluating the force alteration when the tank vent is activated. Depending on the load of the active charcoal filter, the purge air contributes more or less to the formation of the mixture.
- This test is performed independently of the output stage diagnosis.

Diagnostic conditions
- Battery positive voltage 11 ... 15.5 V
- Time after engine starts 600 s
- Engine temperature > 60 °C
- Ambient temperature > 3.8 °C
Vehicle speed = 0 km/h
- Correction factor, height > 0.730
- Active charcoal filter load > 2.0
- No faults detected for hot-film mass air flow meter, throttle valve adjusting unit, tank vent output stage, coolant temperature sensor, vehicle speed, idle speed control

Possible fault causes
- Tank vent faulty (stuck open or closed)
- Tank vent installed back to front
- Purge air line leaking
- Purge air line trapped or blocked