Electronic Suspension Control Diagnosis

DTC C0455

Circuit Description
The digital steering wheel position sensor inputs to the electronic suspension control (ESC) module consists of 3 digital input circuits, phase A, phase B and index marker pulse. The steering wheel position sensor supply voltage is between 4.9-5.1 volts. The information that the ESC module receives from the steering wheel position sensor is used to calculate steering angle, steering velocity and lateral acceleration. These values are used in the control of the suspension dampers.

The digital steering wheel position sensor phase A and phase B circuits are digital pulse signals whose output represents one degree of steering wheel rotation. When observing the phase A data and the phase B data parameters on the scan tool, the parameters will not have the same value at the same time. When the steering wheel is rotated, the phase A data and the phase B data parameters will be shown as high or low on the scan tool.

The index marker pulse is a digital pulse that is displayed as high on the scan tool for 20 degrees only when the steering wheel angle is between -10 and +10 degrees.

Conditions for running the DTC
Turn ON the ignition, with engine ON.

Conditions for Setting the DTC
^ The index marker pulse data parameter is high for less than 20 degrees of the steering wheel angle.
^ The index marker pulse data parameter is high for greater than 20 degrees of the steering wheel angle.
^ The index marker pulse data parameter is high when the steering wheel angle parameter is greater than +90 degrees.
^ The index marker pulse data parameter is high when the steering wheel angle parameter is less than -90 degrees.
^ The steering wheel position sensor phase A circuit is shorted to ground, open or shorted to voltage.
^ The steering wheel position sensor phase B circuit is shorted to ground, open or shorted to voltage.
^ The index marker pulse is shorted to ground, open or shorted to voltage.

Action Taken When the DTC Sets
^ The code is displayed on the scan tool as DTC C0455.
^ The suspension control defaults to firm.

Conditions for Clearing the DTC
^ Conditions for DTC are not currently present.
^ The module receives a clear code command from the scan tool.
^ The DTC clears after 100 malfunction free ignition cycles.

Diagnostic Aids
The following conditions are possible causes:
^ A malfunctioning steering wheel position sensor is present.
^ A steering wheel position sensor circuit is open.
^ A steering wheel position sensor circuit was shorted.
Perform an inspection of the wiring and of the connectors. Failure to carefully inspect the wiring and the connectors may result in misdiagnosis. Misdiagnosis causes part replacement with reappearance of the malfunction. Steering Wheel

Position Sensor-Digital Signal
^ 3 outputs used-Phase A, Phase B. Index Marker Pulse
^ Phase A & Phase B
Offset PWM wave forms created when turning the wheel
^ Index marker pulse
Signal is present only when steering wheel is within 10 degrees either side of center
Output is used to determine Direction of Rotation and Rate of Rotation





Steering Wheel Position Sensor-Digital Signal





Steering Wheel Position Sensor-A and B Phase

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. Test for the proper operation of the phase A circuit.
5. Test for the proper operation of the phase B circuit.
7. Test for the proper operation of the index marker pulse circuit.

Steps 1 - 12:

Steps 13 - 15:

DTC C0455