General information about testing the fuel tank system
The engine management system has a built-in function for carrying out a quick check of fuel tank system sealing. By activating the function, the control module determines faster than usual whether the fuel tank system is fault free or if there is any leakage. The conditions for this test are that
- Engine idling
- The engine coolant temperature (ECT) is higher than 70 °C
- There is not too much fuel in the tank
- Fuel evaporation is not too high during the leakage test (increased evaporation gives a pressure increase in the tank system).
The amount of vaporization permitted varies depending on the leakage test. Higher vaporization is permitted for the 1.0 mm than the 0.5 mm leakage test. If the test for 1.0 mm leaks starts but not for 0.5 mm leaks ("Smallest leak"), it may be because the fuel vaporization is too high.
HINT: There is high vaporization in warm conditions. Vaporization increases also if winter fuel is used in warm conditions. Fuel vaporization can be decreased by allowing the fuel to cool. If there is difficulty spray water on the fuel tank to speed up the fuel cooling down.
For further information about the fuel tank system diagnostic, see Leak diagnostic.
- Canister purge (CP) valve
- EVAP canister
- EVAP canister shut-off valve
- Fuel tank pressure sensor
- Air cleaner (ACL).
Scheme 951
- Continue Refer to «Checking the engine coolant temperature (ECT)»(ref-408511-S32973936432011071200000)
See also:
• Safety regulations for handling fuel
• 9995646