Checking the cause of the problem with quick test
HINT: If the quick test does not start or is prematurely interrupted, it could be because:
- engine temperature is below 30 °C
- there is too much fuel in the tank
- there is high fuel evaporation
- there is a blockage between the tank pressure sensor and the tank
HINT: The method below is used to determine if the problem with the quick test is caused by high evaporation or a blockage between the tank pressure sensor and the tank. This is done by running the test with the tank cap removed. Normally, a major leak is detected if the cap is off.
HINT:
If the canister is filled with fuel vapor, the test is interrupted. The canister fills with fuel vapor more quickly if the canister purge valve is regulating and the tank cap is removed. Therefore, start the quick test immediately after engine start and do not allow the engine to idle more than necessary.
- Remove the tank cap.
- Engine idling
- Start the quick test with the tank cap removed.
Especially check tank pressure (yellow line) during the test for major leaks.
If the quick test is not interrupted when the tank cap is removed and a major leak is detected after quick test completion, fuel evaporation is too high. Fuel evaporation can be reduced by allowing the fuel to cool. Speed cooling by spraying the fuel tank with cold water.
If the quick test is interrupted or a small leak is detected when the tank cap is removed and tank pressure (yellow line) drops more quickly than normal during the test, there may be blockage in a hose or hose connection between the tank and tank pressure sensor. This can be fault traced by detaching the hoses to EVAP system components (one at a time) and performing a quick test for each. If a major leak is detected after the quick test when the hose has been disconnected, the fault is against the direction of airflow (calculated from the disconnected hose).
HINT: Airflow direction during the quick test can be calculated from the fuel tank: fuel tank, canister, canister purge valve, intake pipe. The tank pressure sensor measures the pressure in the hose between the fuel tank and the canister.
HINT: If, for example, the hose to the canister is detached from the fuel tank and a major leak is detected, there is a blockage in the tank hose connection.
Remedy as necessary.
Restore all components and then perform a quick test of the tank system before delivering the vehicle to the customer.
Select an alternative to continue:
- Continue fault tracing for the diagnostic trouble code.
Refer to Starting the quick test
- Exit.
OKAY: Troubleshooting has been completed.
- Continue fault tracing for the diagnostic trouble code.