P0457

P0457-LOOSE FUEL CAP







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 Powertrain Control Module (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:
Engine running. 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:
If a leak greater than.090" is detected by the Powertrain Control Module (PCM) for two consecutive cold start trips after a significant fuel level change, this DTC will set. One good trip turns off the MIL.





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

1. ACTIVE DTC

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

1. Start the engine.
2. Allow the engine to idle.
3. Using the scan tool, perform the ESIM FORCED MONITOR TEST. Allow the test to complete.
4. Using the scan tool, read DTCs.

Is the DTC Active or Pending at this time?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. Intermittent Condition Test.

2. FUEL FILLER CAP VISUAL INSPECTION
Remove the Fuel Filler Cap and visually inspect for the following:

- Loose or missing Fuel Filler Cap or seal
- Damaged locking tabs on the Fuel Filler Cap and/or filler tube
- Damaged seal points on the Fuel Filler Cap and/or filler tube

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. FUEL FILLER CAP
1. Reinstall the Fuel Filler Cap.
2. Start the engine.
3. Allow the engine to idle.
4. Using the scan tool, perform the ESIM FORCED MONITOR TEST. Allow the test to complete.
5. Using the scan tool, read DTCs.

Is the DTC Active or Pending at this time?

Yes

- Replace the Fuel Filler Cap.
- Perform the PCM VERIFICATION TEST. Powertrain Verification Test.

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. Intermittent Condition Test.