P0452

P0452-EVAP PRESSURE SWITCH STUCK CLOSED

For a complete wiring diagram, refer to the Wiring Information





Theory of Operation










The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. At key off, the Powertrain Control Module (PCM) monitors the Evaporative System Integrity Monitor (ESIM) Switch. As the fuel and air in the Fuel Tank cools, a vacuum will occur naturally inside the tank. One inch of vacuum will cause the switch to close. If the PCM sees the switch close before the counter reaches a calibrated amount, the monitor passes.

The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. With the engine running, the monitor will first evaluate the delta pressure change of the Fuel Tank Pressure (FTP) Sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. The intrusive test runs only if stage one does not pass. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.

- When Monitored:
Immediately after the ignition has been turned off.

- Set Condition:
At key off, the Powertrain Control Module (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. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. VEHICLE HISTORY AND SERVICE BULLETIN INVESTIGATION
1. Ignition on, engine not running.
2. With the scan tool, select View DTCs. Record the related Freeze Frame data if any DTCs are present.
3. Whether or not any DTCs are active you will want to check the following items which may assist in repairing the customer's complaint successfully.
- Check the vehicle's repair history.
- If the vehicle has a repair history that pertains to the customer's current complaint, review the repair.
- Inspect the vehicle for any aftermarket accessories that may have been installed incorrectly.
- Check for any service bulletin(s) related to the customer's complaint or DTCs.
- If a service bulletin applies, follow the instructions in the service bulletin.

Choose the following scenario that applies.

The service bulletin repaired the customer's complaint.

- Testing complete.

A DTC is present, no service bulletins apply or the service bulletin didn't repair the customer's complaint.

- Go To 2

2. ACTIVE DTC

NOTE: If the customer is experiencing an early fuel shut off during the fuel filling process along with P0440, P0441 and P0452 setting, you need to check for restrictions in the Evaporative Purge tubes/hoses as well as the Fresh Air Filter before continuing.

1. Ignition on, engine not running.
2. With the scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 3

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

3. ESIM SWITCH STATE
1. With the scan tool, select Data Display and view the ESIM switch state.
2. Disconnect the purge hose from the Evaporative canister.

Does the ESIM switch state change from 'Closed' to 'Open' when the purge hose was disconnected?

Yes

- Go To 4

No

- Go To 6

4. CHECK THE (K52) PURGE CONTROL CIRCUIT SHORTED TO GROUND
1. Disconnect the Purge Solenoid harness connector.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance between ground and the (K52) Purge Control circuit in the Evap Purge Solenoid harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 5

No

- Repair the (K52) Purge Control circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. EVAP PURGE SOLENOID
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Evap Purge Solenoid and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Evap Purge Solenoid and the Powertrain Control Module harness connectors.
4. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace the Purge Solenoid.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. ESIM ASSEMBLY
1. With the scan tool, select Data Display and view the ESIM switch state.
2. Disconnect the ESIM switch harness connector.

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

Yes

- Verify that there is good pin to terminal contact in the Switch and the Powertrain Control Module harness connectors. Replace the ESIM Switch Assembly if no problems were found with the connectors.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. CHECK THE (K108) ESIM SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance between ground and the (K108) ESIM Switch Signal circuit at the ESIM Switch harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 8

No

- Repair the (K108) ESIM Switch signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

8. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Purge Solenoid Assembly, ESIM Switch and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the ESIM, Evap Purge Solenoid and the Powertrain Control Module harness connectors.
4. Perform any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.