Electronic Suspension Control

DTC C0455
Circuit Description
The digital Steering Wheel Position Sensor (SWPS) inputs to the Electronic Suspension Control (ESC) module consists of 3 digital input circuits, phase A, phase B, and index marker pulse. The SWPS supply voltage is between 4.9-5.1 volts. The information that the ESC module receives from the SWPS is used to calculate steering angle, steering velocity, and lateral acceleration. These values are used in the control of the suspension dampers.

The digital SWPS 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.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0455 Front Steering Position Sensor Circuit

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 SWPS phase A circuit is shorted to ground, open, or shorted to voltage.
^ The SWPS 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 SWPS is present.
^ A SWPS circuit is open.
^ A SWPS 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 pulse width modulation (PWM) wave forms created when turning the wheel
^ Index marker pulse-The signal is present only when the 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.