P0441

EVAP CANISTER PURGE VALVE, FLOW





Fault Symptoms.
CHECK ENGINE lamp (MIL) on.
Any other diagnostic trouble codes, closed loop, misfiring.

Conditions.
^ Inlet temperature above -6.7°C.
^ 1,000 seconds after starting.
^ Closed loop active.
^ Vehicle speed 0 km/h.
^ Idling.
^ When the supply air for the evaporative emission canister is shut off, the pressure in the tank drops even though the purge valve is not active.

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

Whether air or fuel vapour is sucked through the valve makes no difference.

Since faults in the purge valve's electrical circuit are indicated by another diagnostic trouble code, fault diagnosis here concerns a mechanical fault.





Diagnostic Procedure.
1. Check the air flow

- Unplug the purge valve's 2-pin connector.
- Disconnect the hose from the evaporative emission canister side of the valve.
- Start the engine and, by means of the pressure gauge on the pressure/vacuum pump, check whether air is sucked into the valve:

Is air sucked in?
YES: Change the valve and 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 coolant temperature exceeds 40°C (104°F) or for at least 1 minute if this temperature is reached earlier.
- Check whether air is sucked into the valve in pulses.

Is the valve pulsing?
YES: Continue with point 3.
NO: Change the valve and continue with point 4.

NOTE: After starting, the purge valve is active for 220 seconds and idle for 130 seconds. Following this, the valve is not active at regular intervals and the time will depend on the control module's fuel adaptation.





3. Check the purge flow from the evaporative emission canister

- Connect the pressure/vacuum pump to the hose from the evaporative emission canister.
- Check whether a steady purge flow is obtained from the evaporative emission canister.

Is a steady purge flow obtained ?
YES: Change the purge valve and continue with point 4
NO: Repair or replace the hose, change the evaporative emission canister if necessary and continue with point 4.





4. 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 code.
- 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.