C0473

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Part 2 Of 2:

CIRCUIT DESCRIPTION
The Passlock/EVO Module supplies a 5.0 volt reference and a ground circuit to the Steering- Handwheel Speed (HWSS) Sensor. The HWSS returns a voltage signal to the Passlock/EVO Module indicating the steering wheel rate of steer. The HWSS returns a voltage 0.2 - 4.9 volts when the steering wheel has been turned one quarter revolution (90 degrees). The Passlock/EVO Module monitors the HWSS signal voltage to control a PWM current (Percentage Duty Cycle) to the Steering Assist Control Solenoid.

CONDITIONS FOR SETTING THE DTC
The HWSS signal circuit voltage is greater than 4.9 volts for one second or longer.

ACTION TAKEN WHEN THE DTC SETS
The Passlock/EVO Module will not send any current to the Steering Assist Control Solenoid. This will cause the solenoid valve to retract, providing maximum fluid flow and full power steering assist at all times.

CONDITIONS FOR CLEARING THE DTC
1. A history DTC will clear after 100 consecutive ignition cycles have occurred without the fault reoccurring.
2. The history and current DTC(s) can be cleared using the scan tool.

DIAGNOSTIC AIDS
The scan tool will read steering wheel position in volts. With the ignition switch in the ON position and as the Steering Handwheel Speed Sensor is rotated, the voltage reading should be 0.2 - 4.9 volts. Voltage should increase at a steady rate up to 4.9 volts when the wheel is turned one quarter revolution (90 degrees) in either direction.
- Above 0.2 volts.
- Below 4.9 volts when the steering wheel is rotated one quarter revolution (90 degrees).
Using the scan tool, scan the HWSS.
- Above 0.2 volts.
- Turn the steering wheel.
- The scan tool display should increase from above 0.2 volts and below 4.9 volts as the steering wheel is turned one quarter revolution (90 degrees).

TEST DESCRIPTION
The Step numbers below refer to the same step numbers in the Steering Handwheel Speed Sensor Signal Voltage High Diagnostic Table.
- Step 2 check prompts the technician to complete some basic checks and store the Snapshot Data. This also allows the technicians to store failure records on the scan tool. This creates an electronic copy of the data taken when the fault occurred. This stored information in the scan tool can be referred to later. When the voltage is 0.2 - 4.9 volts, the Passlock/EVO Module will use this voltage to detect changes in the rate of steering. The system voltage should increase and decrease proportionately to steering wheel rotational speed. If the voltage is not within specifications, an DTC will set. In addition to DTC diagnosis, check for binding, grinding or damaged Steering Handwheel Speed Sensor. Refer to Steering Handwheel Speed Sensor (HWSS) Replacement in this section.
- Step 5 probes the ground circuit checks the circuit for high resistance which will cause a DTC C0473 to set.
- Step 6 verifies a shorted 5.0 volt reference circuit may also set additional DTC's.