Fix Chrysler Dodge P0440, P0441, or P0452 trouble codes
Chrysler vehicles use several different methods to test the integrity of the fuel vapor recovery system in their vehicles. When the tests detect a fault, they’ll set a Chrysler Dodge P0440, P0441, or P0452 trouble code. Later model Chrysler vehicles use the Evap Purge Monitor system to test the integrity of the hoses and tubes the run from the fuel tank to the throttle body and intake.
How the Evap Purge Monitor test works
The test is performed in two stages, where the second test runs only after the EVAP system passes the small leak test. The Evap Purge Monitor test runs with the engine running after a cold start. The difference between the engine coolant temperature and the ambient air temperature must be less than 18° F and the fuel level must be between 12% and 88%. In addition, intake manifold vacuum must be greater than a minimum value and the ambient air temperature must be between 39° F and 89° F, at an altitude of less than 8500 feet.
The test starts when the PCM slowly opens the purge valve
and looks for the Evaporative system integrity monitor switch (ESIM) to close. If the switch doesn’t close after a calculated amount of purge
flow, the PCM sets a pending trouble code. If the pending code sets after three trips, the PCM will turn on the check engine light.
During the test the PCM monitors the purge vapor ratio and the ESIM switch closed ratio. If the purge vapor ratio is above a calculated value, the system passes the test.
If the Evap Purge Monitor fails test #1
The PCM will initiate stage two test only if stage one does not pass. The PCM commands the purge solenoid to flow at a specified rate to force the purge vapor ratio to update. The ratio is
compared to a calibrated specification. If it is less than specified, a one trip failure is recorded. This test can detect if the purge hose is off, obstructed, or the purge valve is not operational.
What causes P0455 Large leak
The PCM activates the purge solenoid connected to the intake manifold. This allows engine vacuum into the fuel system which forces the ESIM switch to close. Once the PCM sees the closed ESIM signal, the PCM deactivates the purge solenoid. At this point, there’s vacuum in the entire fuel system. The PCM monitors the ESIM switch to see if the switch stays closed, which would indicate the EVAP system is sound. If there’s a leak in any of the components, the vacuum will deteriorate and the ESIM switch will open. If the ESIM switch opens before a calibrated amount of time, the PCM sets a pending P0455 large leak code. If the code sets after three trips, the PCM turns on the check engine light.
Causes of P0455
Leak in the purge solenoid vacuum line
Obstruction in the hose/tube to the purge valve
Leak between the purge valve and fuel system
Faulty ESIM switch.
What causes a P0456 small leak
This test is conducted with the ignition OFF, when fuel level is less than 88% and outside temperature is between 39° and 109°. Here’s how the test works. As temperatures change, a vacuum is created in the fuel tank and EVAP system. Since the EVAP system is sealed, the PCM simply monitors the ESIM switch. If the ESIM doesn’t close within a calibrated amount of time, the PCM detects and error. If it detects the error three times, it turns on the check engine light along with a P0456 small leak trouble code.
Causes of P0456
Problem with the EVAP purge solenoid vacuum lines
EVAP system leak
Obstruction in the purge hose/tube
Ground circuit to purge valve is open or has high resistance
EVAP PURGE HOSE/TUBE OBSTRUCTION
Signal circuit to ESIM is open or has high resistance
Faulty EVAP purge solenoid
Faulty ESIM switch
A hot vehicle can conceal a potential leak. Let the vehicle sit until it reaches ambient
temperature before testing
A loose gas cap can cause this trouble code. Make sure the gas cap is tight and in good
If you are having trouble filling the tank with gas
and have any of these trouble codes:
P0440, P0441, or P0452, check for restrictions in the Evap Purge tubes/hoses as well as the Fresh Air Filter before continuing.
©, 2017 Rick MuscoplatPosted on by Rick Muscoplat
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