DTC ECM-4308-II

Condition







When the EVAP canister shut-off valve is closed the fuel tank system should be sealed. When the evaporative emission system (EVAP) valve is activated the fuel tank pressure must fall to a set negative pressure or it will be interpreted as a major leak. Then the evaporative emission system (EVAP) valve closes. The fuel tank pressure must not rise too quickly, this is interpreted as a minor leak. Diagnostic trouble code (DTC) ECM-4308 is stored if the control module registers a minor or major leak.

Substitute value
None.

Possible source

Major leak:
- Leaking fuel tank, filler pipe, fuel tank filler cap, evaporative emission system (EVAP) canister, evaporative emission system (EVAP) canister shut-off valve or lines between these components
- Blocked evaporative emission system (EVAP) valve
- Blocked hoses to the fuel tank pressure sensor or defective fuel tank pressure sensor. Does not react to changes in pressure.

Minor leak:
- Leaking fuel tank, fuel filler pipe, fuel tank filler cap, EVAP canister, canister purge (CP) valve, or in the hoses between these components.

Fault symptom[s]
None.