Diagnostic trouble code (DTC) information

Condition 

The EVAP canister shut-off valve is closed, this means that the fuel tank system is closed. Canister purge (CP) valve is pulsed, pressure in the fuel tank should drop rapidly. Diagnostic trouble code (DTC) ECM-4338 is stored if the pressure in the fuel tank does not drop rapidly enough. This diagnostic trouble code (DTC) is stored in the first operating cycle that the fault is discovered in, in order to warn the driver with a text message that the fuel tank filler cap might be loose or not installed. ECM-4308 Fuel tank system large leak is stored at the same time.

Substitute Value 

Possible Source 

Signal too low: 

• leaking fuel tank, filler pipe, fuel tank filler cap, EVAP canister, EVAP canister shut-off valve or lines between these components.
• blocked canister purge (CP) valve, EVAP canister, fuel tank pressure sensor or pipes between these components.
• sticking canister purge (CP) valve

Faulty signal: 

• blocked canister purge (CP) valve, EVAP canister, fuel tank pressure sensor or pipes between these components
• sticking canister purge (CP) valve
• faulty fuel tank pressure sensor

Fault symptom[s] 

• none