C0508

CIRCUIT DESCRIPTION
The Electronic Variable Orifice (EVO) Module supplies a 5.0 volt reference and a ground circuit to the (SWP) sensor. The SWP sensor returns a voltage signal to the EVO Module indicating the steering wheel rate of steer. The SWP sensor returns a voltage between 0.2 - 4.9 volts when the steering wheel has been turned one quarter revolution (90 degrees). The EVO Module monitors the SWP sensor signal voltage to control a pulse width modulation current (percentage DUTY CYCLE) to the EVO Solenoid.

CONDITIONS FOR SETTING THE DTC
The SWP sensor signal circuit voltage is greater than 4.9 volts for 1 second or longer.

ACTION TAKEN WHEN THE DTC SETS
The EVO Module will not send any current to the EVO Solenoid. This will cause the EVO 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 concurrent ignition cycles have occurred without the fault reoccurring.
2. The history and current DTC(s) can be cleared using the Tech 2 scan tool.

DIAGNOSTIC AIDS
The Tech 2 Scan Tool will read steering wheel position in volts. With the ignition switch in the ON position and as the steering wheel position sensor is rotated, the voltage reading should be between 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 Tech 2, scan the SWP sensor.
- Above 0.2 volts.
- Turn the steering wheel.
- The Tech 2 display should increase from above 0.2 volts and below 4.9 volts as the steering wheel is turned one quarter revolution (90 degrees).

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TEST DESCRIPTION
The step numbers below refer to the same step numbers in the Steering Wheel Position Sensor - Signal Voltage High Diagnostic Table.
1. The system check prompts the technician to complete some basic checks and store the "Freeze Frame" data. This also allows the technicians to store failure records on the scan tool if applicable. 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.
2. When the voltage is between 0.2 and 4.9 volts, the EVO Module will use this voltage to detect changes in the rate of steering and the system voltage should increase and decrease proportional to steering wheel rotation. If the voltage is not within specifications an appropriate DTC will set. In addition to DTC diagnosis, check for binding, grinding or damaged steering wheel position sensor.
5. Probing the ground circuit checks the circuit for high resistance which will cause a DTC C0508 to set.
7. A shorted 5.0 volt reference circuit may also set additional DTCs.
11. Before replacing the EVO Module, check terminals for improper mating, broken locks and physical damage to the wiring harness.