The evaporative emission (EVAP) system is used to store fuel vapors in order to reduce the amount of fuel vapors into the atmosphere. The fuel tank pressure (FTP) sensor is only used for EVAP system diagnostics. The FTP sensor is a transducer that varies resistance according to changes in the fuel tank pressure. The engine control module (ECM) monitors the FTP sensor signal in order to detect vacuum decay and excess vacuum during the EVAP system diagnostic test. The ECM supplies a 5-volt reference and a low reference circuit to the FTP sensor.

P0452

The ECM detects the FTP sensor voltage is less than 0.2 volt.

P0453

The ECM detects the FTP sensor voltage is greater than 4.9 volts.

DTC P0452 and P0453 are Type A DTCs.

DTC P0452 and P0453 are Type A DTCs.

If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. Ignition ON, observe the DTC information with a scan tool. Verify DTCs P0642 or P0643 are not set.

⇒	If DTC P0642 or P0643 is set, refer to DTC P0642, P0643, P0698, or P0699 .

2. Observe the scan tool FTP Sensor voltage parameter. The reading should be between 0.2-4.8 volts.
3. Remove the fuel fill cap. Verify the scan tool FTP sensor voltage parameter is near 0 volts.
4. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

1. Ignition OFF, disconnect the harness connector at the FTP sensor.
2. Ignition ON, test for less than 0.2 volt between the low reference circuit and ground.

⇒	If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

3. Ignition OFF for at least 20 seconds, test for less than 5 ohms of resistance between the low reference circuit and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.

4. IGnition ON, load test for 4.8-5.2 volts between the 5-volt reference circuit and ground.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

5. Verify the scan tool FTP Sensor parameter is less than 4.8 volts.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

6. Install a 3-A fused jumper wire between the signal circuit and the 5-volt reference circuit. Verify the scan tool FTP Sensor parameter is greater than 4.8 volts.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

7. If all circuits test normal, test or replace the FTP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, setup, and programming