P0457-LOOSE FUEL CAP

For a complete wiring diagram Refer to Section 8W.

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 degrees C and 32 degrees C (39 degrees F and 89 degrees F) Close Loop fuel system. Test runs after the medium leak test is inconclusive and the PCM has senses a fuel increase.
Set Condition:
If a leak greater than .090” is detected by the PCM for two consecutive cold start trips after a significant fuel level change, this DTC will set. One good trip turns off the MIL.

Possible Causes

LOOSE OR MISSING FUEL CAP

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING) .

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 repair is necessary. Verify that the gas cap is in place and tight. Clear DTCs and follow the directions outlined in the service information under Instrument Cluster on resetting the odometer or message center display.