P0457

P0457-EVAP SYSTEM - LOOSE FUEL CAP



Theory of Operation

The PCM records the fuel level when the ignition key is turned off and then again when the ignition key is turned back on. This is done to monitor for fuel level increase. If a fuel level increase is detected and the EVAP Leak monitor runs and fails, this DTC will set and the GAS CAP indicator will displayed in odometer to inform the vehicle operator that the cap is off or loose.

- When Monitored:
With the ignition on, ambient temperature between 4° C and 32° C (39° F and 89° F) and the fuel system in closed loop. Test runs after the medium leak test is inconclusive and the PCM senses an increase in fuel level.

- Set Condition:
The PCM activates the EVAP Purge Solenoid to pull the EVAP system into a vacuum which closes the NVLD switch. If the NVLD switch state changes before a calibrated amount of time after a fuel tank fill, an error is detected. Two Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding Pre-Diagnostic Troubleshooting Procedure.
DTC IS ACTIVE

NOTE: If DTC P0455-EVAP SYSTEM LARGE LEAK is set along with this DTC, perform the diagnostic procedure for P0455 before continuing with this test P0455.

NOTE: Do not replace the gas cap for DTC P0457-EVAP SYSTEM - LOOSE FUEL CAP.

1. With a scan tool, select View DTCs.

Is the status Active for DTC P0455-EVAP SYSTEM LARGE LEAK along with this DTC?

Yes

- Perform the diagnostic procedure for P0455-EVAP SYSTEM LARGE LEAK P0455.

No

- No repair is necessary. Verify that the gas cap is in place and tight. Clear DTCs and follow the directions outlined in the Owners Manual on resetting the odometer or message center display.