P0441

EVAP CANISTER PURGE VALVE, LOW FLOW





Symptom Of Fault.
The CHECK ENGINE lamp (MIL) is on. Any other diagnostic trouble codes (closed loop, misfiring)

Conditions.
^ Diagnosis not yet performed this drive cycle.
^ Front heated oxygen sensor OK.
^ Vehicle speed = 0
^ Idling speed
^ Closed loop active.
^ Coolant temperature >60 °C (> 140 °F)
^ No load changes
^ Steady idling speed Additional fuel from purging <10% of engine fuel requirement and no change in closed loop or idle speed control when purging activated.

Diagnostic Help.
The diagnostic trouble code indicates that the flow through the purge valve is too low.
Whether air or fuel vapor is sucked through the, valve is of no importance.
Since a fault in the purge valve's electrical circuit is indicated by a different diagnostic trouble code, fault diagnosis concerns a mechanical fault.
It is important to ensure that no hoses are pinched or kinked.

Checking The Wiring
Intermittent faults may occur as a result of occasional short circuits and breaks in the wiring. Jiggle the leads and in-line connectors at several places and in different directions to reveal faults in the wiring harness. Observe the multimeter, ISAT scan tool or test lamp while carrying out this check.





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 in?
YES: Change the valve and proceed to 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 1 minute if this temperature is reached earlier.
- Check that air is sucked into the valve in pulses.

Does the valve pulsate?
YES: Continue with point 3.
NO: Change the valve and proceed to point 4.

Note The purge valve is active for 4 1/2 minutes and then idle for 1/2 minute, and so on.





3. Check the flow from the evaporative emission canister

- Connect the pressure/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 EVAP canister 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:

- Clear the diagnostic trouble code.
- Perform a driving cycle:

^ Ignition switch in the ON position, A/C switched off and temperature sensor unplugged from the Integrated Central Electronics (ICE) so that the radiator fan runs continuously.
^ Start the engine and run it at idling speed until the temperature of the coolant exceeds 60°C (140°F) or for at least 1 minute if this temperature is reached earlier.
^ Depress the accelerator a second or two and then run the engine at idling speed for 30 seconds. Repeat three times.

- Evaluation of the driving cycle:
- Connect an ISAT scan tool.
- Select "READ ON/OFF".
- Select "DIAGNOSTIC STATUS".
- Select "EVAP"

Does the ISAT scan tool show "NOT READY"?
YES: Repeat the driving cycle.
NO: Check whether the diagnostic trouble code has recurred.

Has the diagnostic trouble code recurred?
YES: Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO: The remedial measure taken was correct.

- Plug the temperature sensor into the ICE.
- Clear the diagnostic trouble code for the temperature sensor in the ICE.