P0452

DTC P0452 or P0453

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC P0452
- Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

DTC P0453
- Fuel Tank Pressure (FTP) Sensor Circuit High Voltage




Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

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.






Conditions for Running the DTC

* The engine is operating.
* The vehicle speed is 0 mph.
* The BARO is greater than 68 kPa.
* The ambient air temperature is greater than -7°C (19°F).
* The fuel level is between 12-88 percent.
* The DTCs run continuously once the above conditions are met for 14 seconds.



Conditions for Setting the DTC

P0452

The ECM detects the FTP sensor signal voltage is less than 0.13 volt for 4 seconds or for a cumulative of 50 seconds.

P0453

The ECM detects the FTP sensor signal voltage is greater than 4.8 volts for 4 seconds or for a cumulative of 50 seconds.


Action Taken When the DTC Sets

DTC P0452 and P0453 are Type B DTCs.


Conditions for Clearing the MIL/DTC

DTC P0452 and P0453 are Type B DTCs.


Diagnostic Aids

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


Reference Information
Schematic Reference

Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Fuel System Description (Fuel System Description)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. DTC P0641, P0642 or P0643 should not be set.

• If a DTC is set, refer to DTC P0641, P0642, P0643, P0651, P0652, P0653, P0697, P0698 or P0699 (P0641) .

2. Observe the FTP Sensor voltage parameter. The FTP sensor voltage should be between 0.1-4 volts.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.



Circuit/System Testing

1. Ignition OFF, remove the fuse that supplies B+ to terminal X2-56 of the ECM.
2. Disconnect the C-420 harness connector at the rear of the fuel tank.
3. Test for less than 5.0 ohms of resistance between the low reference circuit terminal E and ground, at the ECM side of the connector.

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

4. Install the fuse that supplies B+ to terminal X2-56 of the ECM.
5. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground, at the ECM side of connector C-420.

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


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

6. Verify that the FTP Sensor parameter is less than 4.8 volts

• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.

7. At the ECM side of C-420, install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify that the FTP Sensor parameter is greater than 4.8 volts.

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

8. Remove the fuel tank. Refer to Fuel Tank Replacement (Service and Repair) .
9. Disconnect the FTP sensor connector.
10. Inspect the FTP sensor circuits in the fuel tank harness, between the FTP sensor connector and C-420 for the following conditions, and repair as necessary:

* Damaged wiring or terminals
* Open circuits
* Short to ground
* Wire to wire short

11. If all circuits/connections test normal, test or replace the FTP sensor.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Fuel Tank Pressure Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming