C0455

DTC C0455

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 Descriptor
DTC C0455 00
- Front Steering Position Sensor Circuit




Diagnostic Fault Information






Circuit/System Description

The steering angle sensor supplies input circuits to the electronic brake control module (EBCM) from the Phase A and Phase B, the Index Pulse Phase C circuits, and 1 Analog signal circuit for steering wheel angle. The analog signal is used along with the index pulse to calibrate the steering angle sensor (SAS). The SAS position is then determined by Phase A and Phase B signals. The 2 input signals Phase A and Phase B are approximately 90 degrees out of phase. Once calibrated, the EBCM dynamically interprets the relationship between the Phase A and Phase B inputs, and determines the position of the steering wheel and the direction of the steering wheel rotation.


Conditions for Running the DTC

* The ignition is ON.
* Ignition voltage is greater than 9.5 volts.



Conditions for Setting the DTC

* Opens, short to ground, or voltage on the analog signal circuits.
* The calculated steering angle from the steering angle sensor does not correlate with the steering angle calculated from the yaw rate.



Action Taken When the DTC Sets

* The EBCM disables the Vehicle Stability Enhancement System (VSES) for the duration of the ignition cycle.
* The driver information center (DIC) displays the Service Stability System message.
* The Antilock Brake System (ABS) remains functional.
* The VSES Caution indicator turns ON.



Conditions for Clearing the DTC

* The condition for the DTC is no longer present.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.



Diagnostic Aids

* During diagnosis, park the vehicle on a level surface.
* Inspect the vehicle for proper alignment. The vehicle should not pull in either direction while driving straight on a level surface.
* Find out from the customer the conditions under which the DTC was set. This information will help to duplicate the failure.
* The snapshot function on the scan tool can help find an intermittent DTC.



Reference Information
Schematic Reference

Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (Description and Operation)
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)

Scan Tool Reference

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


Circuit/System Verification

With scan tool installed, clear the DTCs. Turn the steering wheel through its full range and back to straight ahead to center SAS. Using a scan tool, observe the Steering Wheel position parameter changes smoothly while turning steering wheel through the entire range. Correlate zero reading with wheels in the straight ahead position. Drive the vehicle through a variety of maneuvers turning to the left, and to the right and straight at a speed greater than 20 km/h (13 mph).

If the DTC did not set as a current DTC see diagnostic aids.



Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the SAS.
2. Test for less than 5 ohm between the low reference circuit terminal 2 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 EBCM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and ground.

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

4. Test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and the signal circuit terminal 6.

• If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the EBCM.

5. Ignition OFF, reconnect the SAS.
6. Disconnect the EBCM harness connector.
7. Test for infinite resistance between the signal circuit pin 6 and ground.

• If less than the specified range, test the signal circuit for a short to ground.

8. Disconnect the SAS.
9. Reconnect the EBCM harness connector.
10. Ignition ON, test voltage of phase A phase B, and phase C. verify that the reading is battery positive voltage for each of the three phases.

• If not the specified value, test the phase A phase B, and phase C circuits for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

11. Ignition OFF, reconnect the SAS. Turn the ignition ON. Using the scan tool, rotate the steering wheel and observe the SAS. Verify the sensor sweeps through the entire range while monitoring the steering wheel as it rotates in degrees from the input signals between circuit phase A and the signal circuit phase B. The rotation in degrees should vary between phase A and phase B without any spikes or dropouts.

• If not within the specified range or is erratic, replace the steering angle sensor.

12. If the sensor test normal, replace the EBCM.



Repair Instructions

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

* Steering Wheel Position Sensor Replacement (Steering Wheel Position Sensor Replacement)
* Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming