P0446

SHUT-OFF VALVE





Fault Symptom.
Marginal effect on emissions.

Conditions.
P0446
^ Engine speed above 80 rpm.
^ Battery voltage 7.5-17 V.
^ Shorting to battery positive (B+).

P0447
^ Engine speed above 80 rpm.
^ Battery voltage 7.5-17 V.
^ Open circuit.

P0448
^ Engine speed above 80 rpm.
^ Battery voltage 7.5-17 V.
^ Shorting to battery negative (B-).

Diagnostic Help.
The shut-off valve can be activated with the ISAT scan tool.
- Select "ACTIVATE".
- Select "EVAP SHUTOFF VALVE".

The command activates the shut-off valve at a frequency of 0.5 Hz for 30 seconds.

Check The Wiring.
Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the wiring at several points and in different directions to ascertain whether the wiring harness, including any connectors, is causing the trouble. Observe the multimeter, ISAT scan tool or test lamp while doing this.





Diagnostic Procedure.
1. Check the shut-off valve's power supply
- Unplug the valve's 2-pin connector.
- Turn the ignition switch to the ON position.
- Connect a test lamp to:
^ pin 1 and battery negative (B-)
The lamp should light up.

Did the lamp light up?
YES: Continue with point 2.
NO: Check and repair or replace the lead between pin 1 and crimped connection J15. Then continue with point 3.





3. Final check

IMPORTANT Fault diagnosis may be interrupted if petrol evaporation is excessive or if the evaporative emission canister is saturated. For fault diagnosis to be possible, proceed as follows:
^ Run the engine at 4000 rpm for two minutes.
^ Switch off the engine and wait for 10 seconds.
^ Start the engine and repeat the final check.

The ISAT scan tool is used to activate diagnosis of the EVAP system. The following conditions must be fulfilled for diagnosis to be possible:
^ Engine running at idling speed.
^ Closed loop active.
^ Vehicle speed 0 km/h.

Carry out diagnosis:
- Connect the ISAT Scan Tool.
- Clear the fault codes. Select "INITIATE".
- Select "EVAP DIAGNOSIS".
- Wait for about two minutes or until the ISAT scan tool reads "READY".
- Obtain a readout of the diagnostic trouble code.

Has the diagnostic trouble code recurred?
YES: Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO: The steps taken to rectify the fault were correct.