P0452

P0452 - EVAP Pressure Switch Stuck Closed






For wiring diagrams, refer to.

• When Monitored: Immediately after key off.

• Set Condition: At key off, the PCM energizes the purge solenoid for a calibrated amount of time (30 seconds maximum) and stores the state of the ESIM switch. The state is evaluated again at the next key on. If the PCM does not detect that the ESIM switch is open, an error is detected. Two trip fault. Three good trips to turn off the MIL.






• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics . Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - DTC is Active

• Allow the vehicle to cool to ambient temperature before continuing with this procedure.

• Start the engine.

• Allow the engine to idle.

• Using the scan tool, perform the ESIM forced monitor Test.

• Monitor the EVAP system monitor switch state during the test.

Does the EVAP system monitor switch state remain CLOSED throughout the test?

Yes

• Go to Test Step 2 => [ Test
Step 2 - EVAP System Monitor Switch State ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC

Test Step 2 - EVAP System Monitor Switch State

• With a scan tool, select data display and view the EVAP system monitor switch state.

• Disconnect the purge hose from the EVAP canister.

Does the EVAP system monitor switch state change from CLOSED to OPEN when the purge hose was disconnected?

Yes

• Go to Test Step 3 => [ Test
Step 3 - EVAP Purge Hose/Tube Obstruction ]

No

• Go to Test Step 6 => [ Test
Step 6 - EVAP System Monitor Switch ]

Test Step 3 - EVAP Purge Hose/Tube Obstruction

• Inspect the EVAP purge hose/tube between the EVAP purge solenoid and the fuel tank and between the fuel tank and the EVAP purge canister for proper routing and installation.

• Make sure the hoses and tubes are not damaged, kinked, or blocked.

Were any problems found?

Yes

• Repair or replace as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 4 => [ Test
Step 4 - EVAP Purge Control Circuit Shorted to Ground ]

Test Step 4 - EVAP Purge Control Circuit Shorted to Ground






• Turn the ignition OFF.

• Disconnect the PCM harness connector.

• Measure the resistance between ground and the EVAP purge control circuit in the EVAP purge solenoid harness connector.

Is the resistance less than 100 ohms?

Yes

• Repair the EVAP purge control circuit for a short to ground.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 5 => [ Test
Step 5 - EVAP Purge Solenoid ]

Test Step 5 - EVAP Purge Solenoid

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EVAP purge solenoid and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace the EVAP purge solenoid.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 6 - EVAP System Monitor Switch

• With a scan tool, select data display and view the EVAP system monitor switch state.

• Disconnect the EVAP system monitor switch electrical connector.

Does the EVAP system monitor switch state change from CLOSED to OPEN when the switch is disconnected?

Yes

• Replace the EVAP system monitor switch.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 7 => [ Test
Step 7 - ESM Signal Shorted to Ground ]

Test Step 7 - ESM Signal Shorted to Ground






• Turn the ignition OFF.

• Disconnect the PCM harness connector.

• Measure the resistance between ground and the ESM signal circuit in the EVAP system monitor switch harness connector.

Is the resistance less than 100 ohms?

Yes

• Repair the ESM signal circuit for a short to ground.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 8 => [ Test
Step 8 - PCM ]

Test Step 8 - PCM

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EVAP purge solenoid and the PCM and between the EVAP system monitor switch and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace and program the PCM.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test