C0500

CIRCUIT DESCRIPTION
The Electronic Variable Orifice (EVO) Module supplies a 0 - 850 milliamperes pulse width modulation current (percent Duty Cycle) to the EVO Solenoid. This current is used to extend or retract the actuator valve inside the solenoid. This in turn will regulate an orifice on the power steering pump causing the fluid flow output to modulate. This results in an increase or decrease in steering wheel efforts. With 0 milliampere supplied to the EVO Solenoid, the valve will be fully retracted providing maximum fluid flow and power steering assist. With 850 milliamperes supplied to the EVO Solenoid, the valve will extend decreasing fluid flow and minimize power steering assist. The EVO Module is constantly adjusting current flow to the EVO Solenoid based on vehicle speed and steering wheel position, thus providing vehicle speed related power steering assist.

CONDITIONS FOR SETTING THE DTC
When there is an open or short to ground or a short to voltage in circuits 1294 or 1295 while the EVO Module is pulsing the current to the EVO Solenoid.
1. When the voltage is below 0 volts.
2. When the voltage is at battery voltage.
3. The above conditions must be met for 1 second or longer.

ACTION TAKEN WHEN THE DTC SETS
The EVO Module will not send any current to the Electronic Variable Orifice (EVO) Solenoid. This will result in the actuator valve retracting, 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 a fault.
2. History and current DTCs can be cleared by using the Tech 2 scan tool.

DIAGNOSTIC AIDS
- If DTCs C0502 or C0503 are present, perform these code tests first.
- An "intermittent" problem may be caused by a poor connection, break in the wire insulation exposing the internal wire, or a wire that is broken inside the insulation.
- The EVO Module and the VCM should be thoroughly checked for terminals that have backed out, broken locks, improperly formed or damaged terminals, weak terminal retaining tension, or for proper routing.
- The EVO Solenoid may be stuck providing uncalculated power steering assist.

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Part 2 Of 2:

TEST DESCRIPTION
The step numbers below refer to the same step numbers in the EVO Tracking Errors Diagnostic Table.
1. This step ensures that the "Diagnostic System Check" is performed.
2. This step checks for short to voltage in circuits 1294 or 1295 with the EVO Module disconnected.
3. This step checks for commanded and actual duty cycle.
4. This step checks the EVO Solenoid harness for a short to voltage with the actuator disconnected on circuits 1294 and 1295.
5. This step checks the EVO Solenoid harness for a short to ground or open with the actuator disconnected on circuits 1294 and 1295.