2010 Cadillac Truck SRX FWD V6-3.0L Page 1504

2010 Cadillac Truck SRX FWD V6-3.0L Page 1504

DTC P0452 and P0453 run continuously when the ignition is ON.

P0454

* DTC P0454 runs only when the engine-off natural vacuum small leak test, P0442, executes.

* This test can run once per engine-off period. The length of the test can be up to 10 minutes.

* A refueling event is not detected.

Conditions for Setting the DTC

P0451

This DTC will set if the controller is unable to re-zero the fuel tank pressure sensor voltage within a calibrated range during the engine-off small

leak test, P0442.

P0452

The fuel tank pressure sensor voltage is less than 0.1V for more than 5 seconds.

P0453

The fuel tank pressure sensor voltage is more than 4.9V for more than 5 seconds.

P0454

If, during the engine-off natural vacuum small leak test, P0442, the ECM detects an abrupt fuel tank pressure signal change, other than a refueling

event, this DTC will set. An abrupt change is defined as a change of 0.45 inch H2O in the span of 1 second.

Action Taken When the DTC Sets

* DTCs P0451 and P0454 are Type A DTCs.

* DTCs P0452 and P0453 are Type B DTCs.

Conditions for Clearing the MIL/DTC

* DTCs P0451 and P0454 are Type A DTCs

* DTCs P0452 and P0453 are Type B DTCs

Diagnostic Aids

P0451 and P0454

* A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot

bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.

* Ensure that the reference port on the fuel tank pressure sensor is unobstructed.

* An fuel tank pressure sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output

controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the

Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic

sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 - EEST

while taking a snapshot.

Reference Information

Schematic Reference

Engine Controls Schematics (LAU) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics

(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring

Repairs/Wiring Repairs)