Circuit Description
The EVO/Passlock™ module supplies a 0-850 milliamperes pulse width modulation (PWM) (percent duty cycle) to the power steering solenoid actuator. This current is used in order to extend or retract the actuator valve inside the solenoid. This in turn will regulate an orifice on the power steering pump, causing a modulation of the fluid flow output. This results in an increase or a decrease in the steering wheel effort. With 0 milliampere supplied to the power steering solenoid actuator, the valve will be fully retracted, providing a maximum fluid flow and power steering assist. With 850 milliamperes supplied to the power steering solenoid actuator, the valve will extend, decreasing the fluid flow and minimizing the power steering assist. The EVO/Passlock™ module is constantly adjusting the current flow to the power steering solenoid actuator based on the vehicle speed and the rate of change of the steering wheel position. This provides the vehicle speed-related power steering assist.
Conditions for Setting the DTC
An intermittent open or a short to the ground is present, or the WHT (1294) wire or the BRN (1295) wire has an open or short to the voltage, while the EVO/Passlock™ module is pulsing the current to the PS solenoid actuator.
The following conditions are present for one second or longer:
| • | The voltage is below 0 volts. |
| • | The voltage is at battery voltage. |
Action Taken When The DTC Sets
The EVO/Passlock™ module will not send any current to the power steering solenoid actuator. This will cause the retraction of the power steering solenoid actuator valve, providing maximum fluid flow and full power steering assist at all times.
Conditions For Clearing The DTC
| • | A history DTC will clear after 100 consecutive ignition cycles have occurred without a fault. |
| • | The history and the current DTC can be cleared by using the scan tool. |
Diagnostic Aids
| • | If DTC C0498, C0499, C0502 or DTC C0593 are present, perform these code tests first. |
| • | The following conditions may cause an intermittent problem: |
| - | A poor connection |
| - | A break in the wire insulation exposing the internal wire |
| - | A wire that is broken inside the insulation |
| • | Thoroughly check the EVO/Passlock™ module and the vehicle control module (VCM) for the following conditions: |
| - | Terminals that have backed out |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Weak terminal retaining tension |
| - | Improper routing |
| • | The solenoid valve may be stuck and does not calculate the power steering assist. Refer to Power Steering System Test . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step ensures that the Variable Effort Steering System Check is performed.
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This step checks for a short to the voltage in the WHT (1294) wire or the BRN (1295) wire with the electronic variable orifice (EVO)/Passlock™ module disconnected.
-
This step checks the PS solenoid actuator harness for a short to the voltage with the solenoid disconnected on the WHT (1294) wire or the BRN (1295) wire.
-
This step checks the PS solenoid actuator harness for a short to the voltage with the solenoid disconnected on the WHT (1294) wire or the BRN (1295) wire.
| • | If voltage is indicated, the WHT (1294) wire or the BRN (1295) wire has a short to the voltage. |
| • | If the voltage is 0 volts, the WHT (1294) wire or the BRN (1295) wire has a short to the ground. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Variable Effort Steering System Check performed? | -- | Go to Step 2 | |
2 |
Are any DTCs present? | -- | Go to the appropriate DTC table | Go to Step 3 |
3 |
Then measure the voltage from terminal A1 to ground. Is voltage present? | -- | Go to Step 5 | Go to Step 6 |
4 | Locate and repair the short to the voltage in the CKT 1294 (WHT) wire or the CKT 1295 (BRN) wire between the EVO/Passlock™ module and the PS solenoid actuator. Did you find and correct a problem? | -- | Go to Step 5 | |
5 |
Then measure for continuity from terminal A1 to ground. Is continuity present? | -- | Go to Step 6 | Go to Step 7 |
6 | Locate and repair the short to ground in the WHT (1294) wire or the BRN (1295) wire between the EVO/Passlock™ module and the PS solenoid actuator. Did you find and correct a problem? | -- | Go to Step 8 | Go to Step 7 |
7 | The problem is intermittent. Refer to Intermittents and Poor Connections in Variable Effort Steering. Is the repair complete? | -- | System OK | -- |
8 |
Did you find and correct a problem? | -- | Go to Diagnostic Aids | -- |
