Circuit Description
The body control module supplies a pulse width modulated (PWM) voltage to the Electronic Variable Orifice (EVO) solenoid as well as a low reference path. The PWM voltage is used to control the current into the solenoid which controls the size of the orifice of the pressure output of the power steering pump. This results in a increase or decrease in steering wheel turning effort.
The body control module is constantly adjusting the PWM voltage and monitoring the current to achieve the desired PWM. The system uses inputs from VSS and the steering handwheel position/speed sensor for the desired PWM output. This provides the vehicle speed related steering assist.
Conditions for Running the DTC
Vehicle speed greater than 8 km/h (5 mph).
EVO solenoid command greater than 5% PWM duty cycle.
Conditions for Setting the DTC
| • | Vehicle speed greater than 8 km/h (5 mph). |
| • | EVO output PWM greater than 5% duty cycle and EVO feed back voltage is less than battery voltage minus 4.0 volts. |
Action Taken When the DTC Sets
| • | The DTC will be stored in memory. |
| • | The body control module will turn off both EVO solenoid outputs for the remainder of the ignition cycle. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 100 consecutive ignition cycles with no malfunction present. |
| • | Using a scan tool |
Diagnostic Aids
| • | A internal short of the electronic variable orifice (EVO) solenoid can cause this DTC to set. |
| • | Normal resistance of the EVO solenoid is from 11 to 13 ohms. |
| • | Perform a visual inspection for loose or poor connections at all related components. |
| • | Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Command both the ON and OFF states. Repeat the commands as necessary.
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Verifies that the body control module is providing voltage to the electronic variable orifice (EVO) solenoid.
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Tests for an open in the ground circuit to the electronic variable orifice (EVO) solenoid.
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Tests if voltage is constantly being applied to the electronic variable orifice (EVO) solenoid.
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Tests for a short to ground.
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Recalibrate the body control module when replacement is necessary.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Steering Assist Schematics | ||||
1 | Did you perform the Variable Effort Steering Diagnostic System Check? | -- | Go to Step 2 | |
Does the EVO solenoid turn ON and OFF with each command? | -- | Go to Diagnostic Aids | Go to Step 3 | |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 4 | Go to Step 5 | |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 8 | Go to Step 10 | |
Does the test lamp remain illuminated (continuously) with each command? | -- | Go to Step 7 | Go to Step 6 | |
Test the EVO solenoid HI circuit of the electronic variable orifice (EVO) solenoid for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 9 | |
7 | Test the EVO solenoid HI circuit of the electronic variable orifice (EVO) solenoid for a short to voltage and an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the electronic variable orifice (EVO) solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 |
10 | Repair the solenoid LO circuit of the electronic variable orifice (EVO) solenoid. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | -- |
11 | Measure the resistance of the electronic variable orifice (EVO) solenoid. Does the resistance measure within the specified value? | 11-13 ohms | Go to Step 13 | Go to Step 12 |
12 | Replace the electronic variable orifice (EVO) solenoid. Refer to Power Steering Solenoid Actuator and Discharge Fitting Replacement Did you complete the replacement? | -- | Go to Step 14 | -- |
Did you complete the replacement? | -- | Go to Step 14 | -- | |
14 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
