DTC P0457: EVAP System Leak Detected Fuel Fill Cap Loose or Missing

Check the fuel fill cap installation.
Is the fuel fill cap installed and properly tightened ?

YES - Go to step 2.

NO - Properly install and tighten the cap 3 clicks, then go to step 19.
Check the fuel fill cap seal (A) and the fuel fill pipe mating surface (B). Verify that the fuel fill cap tether cord (C) is not caught under the cap.

Fig 1: Checking Fuel Fill Cap Seal And Fuel Fill Pipe Mating Surface
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the fuel fill cap seal missing or damaged, is the fuel fill pipe damaged, or is the tether cord caught under the cap ?

YES - Replace the fuel fill cap or the fuel fill pipe, then go to step 19.

NO - Go to step 3.
Turn the ignition switch ON (II).
Clear the DTC with the HDS.
Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.
Is the result OK ?

YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the FTP sensor, or the EVAP canister vent shut valve and the PCM.

NO - Go to step 6.
Turn the ignition switch OFF.
Remove the EVAP canister vent shut valve from the EVAP canister (see EVAP CANISTER VENT SHUT VALVE REPLACEMENT ).
Connect the 2P connector to the EVAP canister vent shut valve.
Turn the ignition switch ON (II).
Do the EVAP CVS ON in the INSPECTION MENU with the HDS.
Check the EVAP canister vent shut valve (A) operation.

Fig 2: Checking EVAP Canister Vent Shut Valve Operation
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Does the valve operate ?

YES - Check the routing of the EVAP canister vent tube, then go to step 18.

NO - Go to step 12.
Turn the ignition switch OFF.
Replace the EVAP canister vent shut valve (see EVAP CANISTER VENT SHUT VALVE REPLACEMENT ).
Turn the ignition switch ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.
Is the result OK ?

YES - Troubleshooting is complete.

NO - Check for poor connections or loose terminals at the FTP sensor, or the EVAP canister vent shut valve and the PCM, then go to step 1.
Reinstall the EVAP canister vent shut valve.
Turn the ignition switch ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.
Is the result OK ?

YES - Troubleshooting is complete.

NO - Check for poor connections or loose terminals at the FTP sensor, or the EVAP canister vent shut valve and the PCM, then go to step 1.