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 Descriptor
DTC C0455: Front Steering Position Sensor CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Steering Angle Sensor 5 Volt Reference Circuit | C0455 | C0455 | C0455 | -- |
Steering Angle Sensor Signal Circuit | C0455 | C0455 | C0455 | -- |
Low Reference Circuit | -- | C0455 | -- | -- |
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. |
| • | A DIC message and/or a warning message may be displayed. |
| • | The Antilock Brake System (ABS) remains functional. |
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 car 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
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for EBCM
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
- Ignition OFF, disconnect the harness connector at the SAS.
- Test for less than 1.0 ohm of resistance between the low reference circuit terminal 2 and ground.
- Ignition ON, test for 4.8 volts between the 5 volt reference circuit terminal 1 and ground.
- Test for 4.8 volts between the 5 volt reference circuit terminal 1 and the signal circuit terminal 6.
- Ignition OFF, reconnect the SAS.
- Disconnect the EBCM harness connector.
- Test for infinite resistance between the signal circuit pin 6 and ground.
- Disconnect the SAS.
- Reconnect the EBCM harness connector.
- 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.
- 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 the sensor test normal, replace the EBCM.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the EBCM. |
| ⇒ | If less than the specified range, test the 12-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
| ⇒ | If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the EBCM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground. |
| ⇒ | 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. |
| ⇒ | If not within the specified range or is erratic, replace the steering angle sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for EBCM replacement, setup, and programming
