P0452 Evap Pressure Switch Stuck Closed

P0452 Evap Pressure Switch Stuck Closed - the ignition is turned off and the PCM has powered down, ambient temperature between 4°C and (39°F) and 43°C (109°F). Set condition, the PCM does not detect the ESIM switch in an open state at any time during the ESIM switch stuck closed diagnostic monitor, an error is detected and failure is set at the next enginge run cycle. Default actions, the MIL light will illuminate.

Possible causes:

• ESIM signal circuit shorted to ground.
• ESIM signal circuit shorted to the ESIM ground circuit.
• Evaporative system integrity monitor (ESIM) switch.
• Pinched/obstructed line between the purge solenoid and fuel tank.
• Purge solenoid.
• Powertrain Control Module (PCM).

Diagnose code P0452 Evap Pressure Switch Stuck Closed

Step 1. ESIM switch state

If the customer is experiencing an early fuel shut off during the fuel filling process in addition to DTC P0440, P0441, or P0452, check for restrictions in the tubes/hoses between the Fuel tank and Evaporative Canister, ESIM , and the ESIM Vent Filter before continuing. Diagnose and repair any purge system or purge solenoid circuit DTC before continuing with this test procedure. Turn the ignition on, with a scan tool, read the ESIM switch state.

What is the state of the ESIM switch?

OPEN, go to step 2.

CLOSED, go to step 3.

Step 2. Evap system inspection

example wiring

Turn the ignition off, perform a visual inspection of the entire evaporative emission system for any of the following conditions:

• Damage or missing components.
• Incorrect routing of hoses and tubes.
• Damage or pinched hoses and tubes.
• Check the wiring harness routing for possible intermittent short to ground of the ESIM wiring.

Were any problems found?

YES, repair as necessary.

NO, testing complete. The condition that caused the fault is intermittent and not present at this time.

Step 3. Check for a blockage in the system

Remove the fuel cap or open the capless fuel filter flap. With the scan tool, read the ESIM switch state.

Does the ESIM switch state change from CLOSED to OPEN when the purge hose was disconnected?

YES, go to step 4.

NO, go to step 6.

Step 4. Evap purge solenoid

Keep lit cigarettes, sparks, flames, and other ignition sources away from the test area to prevent the ignition of explosive gases. Keep the test area well ventilated. Failure to do so may result in possible serious or fatal injury.

Disconnected both vacuum hoses at the evap purge solenoid. After disconnecting the purge solenoid vacuum conenctions, inspect the lines and solenoid for signs of contamination. Using a hand vacuum pump, apply 5 in.hg to the ''engine'' side of the purge solenoid. The purge solenoid should hold vacuum for a minimum of 15 seconds. Start the engine. With the scan tool, navigate to system test, and start the purge vapors system test. Select open to actuate the purge solenoid to the ON position. The vacuum should drop when the solenoid is actuated.

Does the solenoid function as described above?

YES, go to step 5.

NO, verify that there is good pin to terminal contact in the solenoid and PCM harness connectors. Replace the purge solenoid if no problems were found in the connectors.

Step 5. Evap purge hose/tube obstruction

Turn the ignition off. Remove and inspect the purge hose between the purge solenoid and the intake manifold for proper routing, installation, damage, kinks or blockages. Inspect the vacuum port on the manifold for blockages.

Were any problems found?

YES, repair or replace as necessary.

NO, repair the pinched or blocked line between the purge solenoid and the canister or between the canister and the fuel tank.

Step 6. ESIM switch

Disconnect the ESIM harness connector.

Does the ESIM switch state change from CLOSED to OPEN when the switch is disconnected?

YES, replace the ESIM.

NO, go to step 7.

Step 7. Check the ESIM signal circuit for a short to ground

Turn the ignition off, disconnect the PCM harness connector. Check for continuity between ground and the ESIM signal circuit at the ESIM harness connector.

Is there continuity between ground and the ESIM signal circuit?

YES, repair the ESIM signal circuit for a short to ground.

NO, go to step 8.

Step 8. Check for a short between the ESIM signal circuit and the ESIM ground circuit

Check for continuity between the ESIM signal circuit and the ESIM ground circuit at the ESIM switch harness connector.

Is there continuity between the ESIM signal circuit and the ESIM ground circuit?

YES, repair the short between the ESIM signal circuit and the ESIM ground circuit.

NO, go to step 9.

Step 9. Check related PCM and component connections

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