DME 7.2

P0446
95 EVAP Canister Shutoff Valve (Function) - Below Limit

Function
The task of the shutoff valve is to seal the purge air line to the EVAP canister during the fuel tank leak test.

Diagnosis conditions
- Oxygen sensing system active
- No secondary air diagnosis
- Air mass < 30 kg/h
- Engine running
- Vehicle speed = 0 km/h
- Intake air temperature between 5 °C and 50 °C
- Engine starting temperature between 5 °C and 55 °C
- Battery voltage > 11 V
- Engine load < 30 %
- Altitude correction factor > 0.75
- EVAP canister burden < 3
- Time elapsed after engine start-up > 990 seconds or mixture adaptation completed
- No faults in: Throttle position sensor, idle air control, vehicle speed, EVAP canister purge valve, mass air flow sensor, voltage supply, pressure sensor, shutoff valve and engine temperature

NOTE: Fuel tank ventilation diagnosis is initiated with the Porsche System Tester 2 in the "Short test" menu. This reduces the time elapsed after engine start-up to 30 seconds.







NOTE: The EVAP canister purge valve is very sensitive to contamination. If the lines to the EVAP canister have to be detached, the outside of the canister must be cleaned beforehand.

System Overview:

Diagnosis Procedure:

1 Check purge air line for blockage.

1. Remove front right-hand wheel housing liner.
2. Detach purge air line (connection face up) from EVAP canister.
3. Blow through purge air line with compressed air.