DTC 3-1-5

3-1-5 EVAP SYSTEM

Preconditions for DTC






Monitoring of the EVAP system's function begins about 17 minutes after the engine has been started, and takes place when the engine is at idling speed. If the Idle Air Control (IAC) valve's idle air trim and short term fuel trim do not need to make any adjustments to compensate for EVAP valve activation, this is interpreted as a fault and DTC 3-1-5 is set.

Substitute value

Fuel trim is inhibited.

Fault sources

Clogged canister.
Clogged hoses.
Defective EVAP valve (permanently open or shut).

Fault symptoms

Fuel odor from EVAP canister (in warm climate).
Possibly high idling speed.

TESTING PROCEDURE

Other DTCs






Read off other DTCs.
If DTC 5-4-1 is stored:
- See: Testing By Trouble Code, DTC 5-4-1 EVAP Valve Signal.
If DTC 5-4-1 is not stored:
- Proceed to: Check of vacuum to EVAP valve section below.

Check of Vacuum to EVAP Valve






To gain access to the EVAP valve, remove the following:
Valve from the bracket.
Possible noise insulation from the valve.
Refit the valve, hoses and sound insulation after fault tracing. When re-installing, use pliers P/N 9814215 and fit a new hose clamp.
START the engine and let it run at idling speed.
Undo the hose between the EVAP valve and the intake manifold from the EVAP valve.
Check that there is vacuum in the hose.

If there is vacuum:
- Check of vacuum after the EVAP valve.
If there is no vacuum:
- Check if the hose between the EVAP valve and intake manifold is clogged.
- Check also the hose connection to the intake manifold.

Check of Vacuum After the EVAP Valve






Engine at idling speed.
Connect the hose between the EVAP valve and the intake manifold to the EVAP valve.
Undo the hose between the EVAP valve and canister from the EVAP valve.
Check that there is no vacuum in the EVAP valve when the valve is not activated.
Use the parameter in the DTC parameter list to determine whether or not the EVAP valve is activated.

If there is no vacuum:
- Check the EVAP valve.
It there is vacuum:
- Test with a new EVAP valve.

Checking the EVAP Valve






Engine at idling speed.
The hose between the EVAP valve and canister is undone at the EVAP valve.
Check that there is vacuum in the EVAP valve when the valve is activated.
The EVAP valve is activated within approx. 1 minute after the engine is started. Use the parameter in the DTC parameter list to determine whether the EVAP valve is activated or not.

If there is vacuum:
- Check of vacuum at canister.
It there is no vacuum:
- Test with a new EVAP valve.

Checking of Vacuum at Canister






Engine at idling speed.
Connect the hose between the EVAP valve and canister to the EVAP valve.
Undo the hose between the EVAP valve and canister from the canister.
Check that there is vacuum in the hose when the EVAP valve is activated.
The EVAP valve is activated within about 1 minute after the engine is started. Use the parameter in the DTC parameter list to determine whether the EVAP valve is activated or not.

If there is vacuum:
- Check that all the canister's inlets and outlets are OK.
- If they are all OK: The fault is intermittent.
If there is no vacuum:
- Check if the hose between the EVAP valve and canister is clogged.

INTERMITTENT FAULT






Checking Hoses and Connections
Check the hose between the EVAP valve and the intake manifold to ensure it is not clogged or pinched.
Check the hose between the EVAP valve and canister to ensure it is not clogged or pinched.
Check the canister connections to ensure they are not clogged.
Check the EVAP valve for dirt and deposits. Test also in DTM 3 that no functional disruption occurs with the EVAP valve.

If no faults can be found in-the above checks:
- Test with a new EVAP valve.