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DTC P0452 or P0453 (LAU)

DTC P0452 or P0453 (LAU)

Diagnostic Instructions


• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptors

DTC P0452

Fuel Tank Pressure Sensor Circuit Low Voltage

DTC P0453

Fuel Tank Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
5-Volt Reference P0452, P0642 P0452, P0641 P0453, P0643 P0641, P0642, P0643
Fuel Tank Pressure Sensor Signal P0452 P0452 P0453 -
Low Reference - P0446 - -


Typical Scan Tool Data

Fuel Tank Pressure Sensor

Circuit Short to Ground Open Short to Voltage
Operating Conditions: Engine operating in Closed Loop at idle Parameter Normal Range: 0.2-4.8 V
5-Volt Reference 0 V 0 V 5 V
Fuel Tank Pressure Sensor Signal 0 V 0 V 5 V
Low Reference - 4.2 V -


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 sensor is only used for EVAP system diagnostics. The fuel tank pressure sensor is a transducer that varies resistance according to changes in the fuel tank pressure. The engine control module (ECM) monitors the fuel tank pressure 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 fuel tank pressure sensor.

Fuel Tank Pressure Sensor Signal Voltage Fuel Tank Pressure
High, Approximately 1.5 Volts or More Negative Pressure/Vacuum
Low, Approximately 1.5 Volts or Less Positive Pressure


Conditions for Running the DTC


• The engine is operating.

• The DTCs run continuously once the above conditions are met for 14 seconds, 10 seconds for LLT.


Conditions for Setting the DTC

P0452

The ECM detects the fuel tank pressure sensor signal voltage is less than 0.12 volt for 4 seconds, or a cumulative of 30 seconds.

P0453

The ECM detects the fuel tank pressure sensor signal voltage is greater than 4.85 volts for 4 seconds, or a cumulative of 30 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 (3.0L (LF1)) Engine Controls Schematics (2.8L (LAU))

Connector End View Reference

Component Connector End Views

Description and Operation

Evaporative Emission Control System Description

Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification


1. Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTCs P0641, P0642 or P0643 should not set.

2. If a DTC is set, refer to DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM, LAU) .

3. Observe the Fuel Tank Pressure Sensor voltage parameter. The Fuel Tank Pressure sensor voltage should be between 0.13-4 volts.

4. 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, disconnect the harness connector at the B150 fuel tank pressure sensor.

2. Ignition OFF, test for less than 5 Ω of resistance between the low reference circuit terminal 1 and ground.

3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

4. Ignition ON, test for 4.8-5.2V between the 5V reference circuit terminal 3 and ground.

5. If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

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

7. Verify the scan tool B150 fuel tank pressure sensor parameter is less than 0.2V.

8. If greater than the specified range, test the signal circuit's pin 2 for a short to voltage. If the circuit tests normal, replace the K20 ECM.

9. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5V reference circuit terminal 3. Verify the scan tool fuel tank pressure sensor parameter is greater than 4.7V.

10. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

11. If all circuits test normal, test or replace the B150 fuel tank pressure sensor.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Fuel Tank Pressure Sensor Replacement

• Control Module References for ECM replacement, setup, and programming