DTC 5-4-1

5-4-1 EVAP VALVE, SIGNAL

Preconditions for DTC
^ If the ECM registers a fault in the EVAP valve's coil or leads from the valve, DTC 5-4-1 is set.

Substitute values
^ Idle air trim inhibited.
^ Fuel trim inhibited.
^ Conditions for fuel shut-off changed.

Fault sources
^ Signal too high:
- Signal lead short circuited to voltage supply.
- Defective EVAP valve.

^ Signal too low:
- Signal lead short circuited to ground.
- Break in signal or voltage supply lead.
- Defective EVAP valve.

Fault symptoms
^ May result in poorer performance.
^ May result in fuel smell in the car.
^ May result in uneven idling speed.

TESTING PROCEDURE





Status Message
^ Check current status message.

If Status message is: Permanent fault, signal too high:
- Proceed to: PERMANENT FAULT, SIGNAL TOO HIGH section below.
If Status message is: Permanent fault, signal too low:
- Proceed to: PERMANENT FAULT, SIGNAL TOO LOW section below.
If Status message is: Intermittent fault, signal too high:
- Proceed to: INTERMITTENT FAULT, SIGNAL TOO HIGH section below.
If Status message is: Intermittent fault, signal too low:
- Proceed to: INTERMITTENT FAULT, SIGNAL TOO LOW section below.

PERMANENT FAULT, SIGNAL TOO HIGH





Checking the EVAP Valve
^ To gain access to the EVAP valve, remove the following:
- Valve from the bracket.
- Sound insulation from the valve.
- Refit the valve, hoses and sound insulation after the fault tracing process.
- For re-installation, use pliers P/N 9814215 and a new hose clamp.
^ Switch Ignition OFF.
^ Disconnect the EVAP valve.
^ Connect an ohmmeter between EVAP valve connector 1 and 2.

The ohmmeter should show approx. 26 ohms at +20°C (68°F).

If the reading is OK:
- Check the lead between EVAP valve connector 2 and ECM A39 for signs of short circuiting to voltage supply.
If the reading is incorrect:
- Test with a new EVAP valve.

PERMANENT FAULT, SIGNAL TOO LOW





Checking the Voltage Lead
^ To gain access to the EVAP valve, remove the following:
- Valve from the bracket.
- Sound insulation from the valve.
- Refit the valve, hoses and sound insulation after the fault tracing process.
- For re-installation, use pliers P/N 9814215 and a new hose clamp.
^ Switch Ignition OFF.
^ Disconnect the EVAP valve.
^ Switch Ignition ON.
^ Connect a voltmeter between EVAP valve connector 1 and ground.

The voltmeter should show battery voltage.

If the reading is OK:
- Check the signal lead's resistance to ground.
If the reading is incorrect:
- Check the lead between EVAP valve connector 1 and main relay (2/32) connector 3 for signs of a break.





Checking the Signal Lead's Resistance to Ground
^ Switch Ignition OFF.
^ Wait for approx. 150 seconds.
^ EVAP valve disconnected.
^ Connect an ohmmeter between EVAP valve connector 2 and ground.

The ohmmeter should show 25 - 40K Ohms.

If the reading is OK:
- Check the EVAP valve.
If the ohmmeter shows infinite resistance:
- Check the ECM connector.
If the ohmmeter shows approx. 0 ohms:
- Check the lead between EVAP valve connector 2 and ECM A39 for signs of short circuiting to ground.





Checking the EVAP Valve
^ Switch Ignition OFF.
^ EVAP valve disconnected.
^ Connect an ohmmeter between EVAP valve connector 1 and 2.

The ohmmeter should show approx. 26 ohms at +20°C (68°F).

If the reading is OK:
- The source of the DTC is poor contact in the EVAP valve's and/or ECM's connector.
- Rectify the connectors with regard to loose connection, contact resistance and oxidation.
If the reading is incorrect:
- Test with a new EVAP valve.





Checking the ECM Connector
^ Switch Ignition OFF.
^ EVAP valve disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.
^ ECM connected.





^ Connect an ohmmeter between EVAP valve connector 2 and ground.

The ohmmeter should show 25 - 40K ohms.

If the reading is OK:
- The fault source is poor contact in the ECM connection.
If the reading is incorrect:
- Check the lead between EVAP valve connector 2 and ECM A39 for signs of a break.

INTERMITTENT FAULT, SIGNAL TOO HIGH





Checking the Leads and Connections
^ Check the lead between EVAP valve connector 2 and ECM A39 for signs of intermittent short circuiting to voltage supply.

INTERMITTENT FAULT, SIGNAL TOO LOW

Checking the Leads and Connections
^ Check the EVAP valve's and ECM's connector for signs of loose connection, contact resistance and oxidation.
^ Check the lead between EVAP valve connector 1 and main relay (2/32) connector 3 for signs of an intermittent break.
^ Check the lead between EVAP valve connector 2 and ECM A39 for signs of an intermittent break as well as intermittent short circuiting to ground.