Blog - DTC Decoded: Dodge P0455

Diagnostic code: P0455

Make: Dodge

Decode: Leak detected in the evaporative emission control system

Code detection: This code indicates that there is a lack of purge flow or a fuel vapor leak within the EVAP control system. This means there is a large leak.

Dodge Evap System

Symptoms of this code:

  • No noticeable drivability symptoms of this code
  • Check engine light is on
  • Fuel odor

What causes this code?

  • A loose gas cap
  • An improper gas cap has been installed
  • Damage or leak within the EVAP system such as hoses or the canister
  • Fuel filler cap failed to close
  • Leak within the fuel tank

What the techs say:

This is a common code, and it generally means that the fuel cap is not properly set or is incorrect for the vehicle.

You can try the following to fix it:

  • Reinstall the gas cap
  • Clear the code by disconnecting the battery for 30 minutes

Once you have cleared the code, drive the vehicle for a few days to see if the code comes back on.

Should the code come back and you have replaced the gas cap, you should do a complete inspection of your fuel system to determine whether there is a cut or hole in any of the tubes in the EVAP system. You may hear a hissing sound or smell a fuel odor. Replace or repair any damaged hose.

Dodge Code Description:

P0455 OBD-II

The EVAP system prevents the fuel vapors from escaping the fuel system. The vapors are routed through a charcoal canister via hoses for storage. Intake vacuum siphons the vapors to the engine when it is running by way of the purge control valve opening.

The PCM does a check for electrical and mechanical malfunctions by checking the leak detection pump (LDP). As long as the first checks all pass, the PCM will use the LDP to seal the valve on the vent and pressurize the system by pumping air into it. Should there be a leak, the PCM continues to pump air into the LDP in order to replace the lost air. This aids in the diagnosis of the size of the leak. The leak size is determined by how long or fast it must pump the LDP in order to maintain system pressure.