P0441

EVAP CANISTER PURGE VALVE, LOW FLOW





Fault Symptom.
CHECK ENGINE lamp (MIL) on.

Conditions.
P0441
^ Diagnosis not yet performed this trip.
^ Speed = 0.
^ Idling speed.
^ Engine coolant temperature > 60°C.
^ > 18 minutes since engine started.

Diagnostic Help.
The diagnostic trouble code indicates that a flow exists even though the purge valve is closed.

Whether air or fuel vapor is sucked through the valve is of no importance.

Diagnosis of the EVAP canister purge valve can be activated with the ISAT scan tool.
- Select "INITIATE".
- Select "EVAP".

On completion of diagnosis the ISAT scan tool will show "READY", otherwise "NOT READY".

The EVAP canister purge valve can be activated by means of the ISAT scan tool.
- Select "ACTIVATE".
- Select "EVAP".

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 air flow

- Unplug the purge valve's 2-pin connector.
- Disconnect the hose on the evaporative emission canister side of the valve.
- Start the engine and use the pressure gauge on the pressure/vacuum pump to check that no air is sucked into the valve.

Is air sucked into the valve?

YES:
^ Change the valve. Continue with point 4.
NO:
^ Continue with point 2.

2 Check the valve

- Switch off the engine and plug in the purge valve's 2-pin connector.
- Start the engine and run it until the temperature of the coolant exceeds 60°C (140°F) or for at least one minute if this temperature is reached earlier.
- Check that air is sucked into the valve in pulses.

Is the valve pulsing?

YES:
^ Continue with point 3.
NO:
^ Change the valve. Continue with point 5.


NOTE: The valve is active/inactive at varying intervals.


3 Check the flow from the evaporative emission canister

- Connect the vacuum pump to the hose from the evaporative emission canister.
- Check that a steady flow is obtained from the evaporative emission canister.

Is a steady flow obtained?

YES:
^ Change the purge valve. Continue with point 5.
NO:
^ Repair or replace the hose and also change the evaporative emission canister, if necessary. Continue with point 5.





4 Check the valve's power supply. Unplug the connector from the EVAP canister purge valve.

- Connect the test lamp to:
^ pin 1 and battery negative (B-).
- Turn the ignition switch to the ON position.
The test lamp should light up.
- Connect the test lamp to:
^ pins 1 and 2.
- Start the engine and run it at idling speed.
The test lamp should light up or start flashing.

NOTE: The valve is active/inactive at varying intervals.

Test lamp on as above?

YES:
^ Change the valve. Continue with point 5.
NO:
^ Check The Wiring connected to the control module for continuity and shorting. Rectify any faults. Continue with point 5.





5 Final check

The ISAT scan tool is used to activate diagnosis of the EVAP emission system. For diagnosis to be possible, the following conditions must be fulfilled:

^ Engine running at idling speed.
^ Closed loop active.
^ Vehicle speed = 0 km/h.

Perform diagnosis:

- Connect an ISAT scan tool.
- Clear the fault code.
- Select "INITIATE".
- Select "EVAP DIAGNOSIS".
- Wait for about 2 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.

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 2 minutes.
^ Switch off the engine and wait for 10 seconds.
^ Start the engine and repeat the final check.