P0442

P0442

Diagnosis information - DME V8 DFI

Tank system leak

Diagnostic conditions
- Short test Tank leak test

or:

- Vehicle voltage 9 V ... 16 V
- Ambient air pressure > 730 hPa (below approx. 2,400 ... 2,700 m above sea level)
- Engine temperature 5 °C ... 50 °C (41 °F ... 122 °F)
- Intake air temperature > 5 °C (41 °F)
- Fluctuations in the intake air temperature of less than 10 °C (18 °F)
- Time after engine start 5 seconds ... 20 minutes
- Steady speed with longer partial-load share for > 150 seconds
- Vehicle acceleration/deceleration -2 m/s2 ... +2 m/s2
- Vehicle speed 7 ... 120 km/h (4 ... 75 mph)
- Height difference < 20 meters

Possible fault causes
- Tank cap not closed correctly
- Tank cap faulty
- Vacuum system leaking
--> The system consists of the mechanical vacuum pump (on the vehicle engine), the leakage diagnosis pump, the intake pipe switch-over valve and, where appropriate, the exhaust flaps in the rear muffler
- Vacuum pump faulty
- Tank vent valve has mechanical fault (does not close completely)
- Internal (diaphragm) or external leak in leakage diagnosis pump
- Tank system (incl. hoses) leaking