FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Major Leak. Permanent Fault






Major leak. Permanent fault

Safety
First read Safety regulations for handling fuel Safety Regulations For Handling Fuel.

Continue - Checking cables and terminals

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Checking cables and terminals
Check that the fuel tank filler cap is on properly and that its seal is intact.
Check hoses and hose connectors at the EVAP canister, EVAP canister shut-off valve and fuel tank.
Remedy as necessary.
Carry out a quick test of the fuel system.

Continue - General about fuel tank system test

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General about fuel tank system test
The engine management system has the built-in function of carrying out a quick check of fuel tank system sealing. By activating the function the control module determines if the fuel tank system is fault free or if there is any leakage faster than usual. The condition for the test is that no diagnostic trouble codes (DTCs) are stored, engine temperature is above 70 °C (158°F) and that the engine is idling.
For further information about fuel tank system test diagnostic, see Leak diagnostic Leak Diagnostic.
1. Canister purge (CP) valve
2. EVAP canister
3. EVAP canister shut-off valve
4. Fuel tank pressure sensor
5. Air cleaner (ACL)

Location Of Components:






Continue - Checking engine coolant temperature (ECT)

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Checking engine coolant temperature (ECT)

Note! If the engine coolant temperature (ECT) is under 70 °C (158°F) the test cannot start.




- Start the engine.
- Read off engine coolant temperature (ECT)
If the engine coolant temperature (ECT) is under 70 °C (158°F) allow the engine to reach operating temperature or interrupt the test.





Is the temperature above 70 °C (158°F)?

Yes - Start the fuel tank system test

No - FAULT TRACING FAILED

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Start the fuel tank system test

Note! If the engine coolant temperature (ECT) is under 70 °C (158°F) the test cannot start.




- Engine idling.
- Start the quick test

Leak diagnostic active
This parameter displays that test is underway. When the parameter displays YES and has returned to NO the test is ready or has been interrupted.

Fault status
These parameters display the status of those diagnostic tests which are included in the leak diagnostic.

The following alternatives are available:
1. When the active leak diagnostic has displayed YES and then NO and all fault status have moved to clear, fault not found, the test has been run without any faults being found.
2. When the active leak diagnostic has displayed YES and then NO and one of the fault status displays fault found. A fault has been detected in that part of the test.
3. When the active leak diagnostic has displayed YES and then NO and one or several of the fault statuses has not gone and no fault is detected.
Or if active leak diagnostic unchanged status to YES.
The test has not started or been interrupted.
Try again or select 3 to interrupt.





Select an alternative?

1 - FAULT FOUND

2 - Checking vacuum downstream of the canister purge (CP) valve

3 - FAULT-TRACING FAILED

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Checking vacuum downstream of the canister purge (CP) valve




- Start the engine and let it idle.
- Disconnect the hose between the canister purge (CP) valve and EVAP canister from the canister purge (CP) valve.
- Read off canister purge (CP) valve. This is to check whether the valve is activated.
Check that there is vacuum in the canister purge (CP) valve when the valve is activated.









Is there a vacuum?

Yes - Checking vacuum at EVAP canister

No - Checking vacuum to canister purge (CP) valve

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Checking vacuum at EVAP canister




- Ignition off.
- Reinstall hose on canister purge (CP) valve.
- Disconnect hose to canister purge (CP) valve from EVAP canister.
- Start the engine and let it idle.
- Read off the canister purge (CP) valve value to determine whether the valve is activated or not.
Check that there is vacuum in the hose when the canister purge (CP) valve is activated.









Is there a vacuum?

Yes - Checking EVAP canister

No - Checking hose

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Checking vacuum to canister purge (CP) valve




- Connect hose between canister purge (CP) valve and EVAP canister to canister purge (CP) valve.
- Start the engine and let it idle.
- Disconnect hose between canister purge (CP) valve and intake manifold from the canister purge (CP) valve.
Check that there is a vacuum in the hose.
Remedy as necessary.





Was a fault detected?

Yes - Verification

No - Replacing component

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Replacing component
Try a new canister purge (CP) valve according to Replacing the canister purge (CP) valve Replacing the Canister Purge (CP) Valve.





Continue - Verification

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Checking EVAP canister
Check that all EVAP canister inlets and outlets are airtight.

Hint: Connect a vacuum pump to the EVAP canister terminals, one at a time, check that it is not possible to pump vacuum.

Other information:
- To access/replace the EVAP canister shut-off valve see.

Was a fault detected?

Yes - Verification

No - Checking hose between fuel tank and EVAP canister

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Checking hose
Check if the hose between the canister purge (CP) valve and EVAP canister is blocked or trapped.

Continue - Verification

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Checking hose between fuel tank and EVAP canister
Check that the hose between the fuel tank and EVAP canister is airtight and is not trapped.
Remedy as necessary.

Was a fault detected?

Yes - Verification

No - Test pressurization of the fuel tank system

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Test pressurization of the fuel tank system




- Max 50 liters of fuel in the fuel tank.
- Ignition off.
- Connect hose from fuel tank to EVAP canister.
- Clamp hose between EVAP canister shut-off valve and EVAP canister with a hose clip to seal it off.
- Carefully disconnect the EVAP canister hose from the canister purge (CP) valve.
Connect manometer 999 5646 Pressure gauge 999 5646 Pressure Gauge to hose and pressure regulator 999 5544 REGULATOR 999 5544 Regulator to manometer.
Set pressure to 7 kPa (1.02 psi) (read off on the manometer 999 5646 Pressure gauge 999 5646 Pressure Gauge ).
Cock at right angles to the hoses.

Warning! Max 10 kPa (1.45 psi).

Let the pressure build up for 5 minutes.
Shut off the cock (the pressure may drop 1-2 kPa (0.15-0.29 psi) before stabilizing) and read off pressure.
EVAP canister hose cock.
Wait for 10 minutes.

Warning! Never leave the car unattended with its fuel tank system pressurized.

The pressure should be stable (it may rise a little due to fuel evaporation).









Is the pressure stable?

Yes - Checking fuel tank pressure sensor

No - Checking fuel tank system

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Checking fuel tank pressure sensor




- Disconnect tool 999 5646 Pressure gauge 999 5646 Pressure Gauge.
- Connect EVAP canister hose.
- Remove hose clamp from hose between canister purge (CP) valve and intake manifold.
- Start the engine and let it idle.
- Read off fuel tank pressure and canister purge (CP) valve value.
When the canister purge (CP) valve opens the pressure in the fuel tank should drop.





Is pressure in the fuel tank dropping?

Yes - Checking hose to EVAP canister shut-off valve

No - Checking fuel tank pressure sensor hose

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Checking hose to EVAP canister shut-off valve
Check hose to EVAP canister shut-off valve seal and check connectors.
Remedy as necessary.

Was a fault detected?

Yes - Verification

No - Replacing component

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Checking fuel tank pressure sensor hose




- Ignition off.
- Remove fuel tank pressure sensor.
- Remove hose with Y-nipple.
Check that the nipple and hoses are not blocked.
Remedy as necessary.

Other information:
- To access/replace the fuel tank pressure sensor see Replacing fuel tank pressure sensor Removal and Replacement.

Was a fault detected?

Yes - Verification

No - Replacing component

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Replacing component
Try a new fuel tank pressure sensor according to Replacing fuel tank pressure sensor Removal and Replacement.





Continue - Verification

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Replacing component
Try a new EVAP canister shut-off valve.





Continue - Verification

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Checking fuel tank system
- Ignition off.
- Carefully pressurize the fuel tank system to 7 kPa (1.02 psi). Cock at right angles to the hoses.

Note! Max 10 kPa (1.45 psi).

Check fuel tank system by spraying soapy water from the EVAP canister to the canister purge (CP) valve. Spray the line between the fuel tank and EVAP canister shut-off valve. Check filler pipe and fuel tank filler cap.
It may be necessary to lower the fuel tank in order to fault-trace hoses and connectors on top of the fuel tank.
Remedy leakage.









Continue - Verification.

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Verification




Verification








- Ignition off.
- Reinstall all hoses/components.
- Start the engine.
Activate the quick fuel tank system test.





Does the diagnostic trouble code (DTC) recur?

Yes - VERIFICATION FAILED

No - VERIFIED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Safety

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