P0457

P0457-LOOSE FUEL CAP





For a complete wiring diagram Consult Diagrams/Electrical.

Theory of Operation

Fuel level is recorded when the ignition key is turned off and is compared to the fuel level when the ignition key is turned back on. The PCM recognizes an increase in fuel level and will fail the Medium leak test because the fuel cap is broken or not installed properly. GAS CAP will be displayed in odometer to inform the owner that the cap is off of loose.

- When Monitored:
Ignition on. Ambient Temperature between 4° C and 32° C (39° F and 89° F). Close Loop fuel system. Test runs after the medium leak test is inconclusive and the PCM has senses a fuel increase.

- Set Condition:
The PCM activates the Evap Purge Solenoid to pull the Evap system into a vacuum to close the ESIM switch. Once the ESIM switch is closed, the PCM turns the Evap Purge Solenoid off to seal the Evap system. If the ESIM switch reopens before the 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 Initial Inspection and Diagnostic Overview.

Diagnostic Test

1. 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.

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

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.

No

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