Circuit Description
The EBCM controls a bi-directional magnetic rotary solenoid. The solenoid is in the steering gear. The solenoid adjusts the amount of power steering assist in order to achieve a given level of driver effort in turning the vehicle. The EBCM varies the steering assist by adjusting the current flow through the solenoid. The amount of steering assist adjusted for steering is dependent upon vehicle speed. As the vehicle speed increases, the following actions occur:
| • | The steering assist decreases. |
| • | The driver effort increases. |
As the vehicle speed decreases, the following actions occur:
| • | The steering assist increases. |
| • | The driver effort decreases. |
Conditions for Running the DTC
The EBCM performs 2 diagnostic tests for the VES circuits when the ignition voltage is between 10.5 volts and 17 volts. The numbers below corresponds to the numbers in Conditions for Setting the DTC.
- Off State Test (Open Circuit Test) - When the ignition is first turned ON, the EBCM performs an open circuit test independent of vehicle speed or engine running.
- On State Test (Open or Short Circuit Test) - If the Off State Test is passed, the EBCM runs the On State Test during VES operations. The VES operations occur during driving. The EBCM detects an open or short in the VES circuit by comparing the feedback current to the commanded current.
Conditions for Setting the DTC
The EBCM performs 2 different tests to detect a DTC condition. The numbers below correspond to the number in Conditions for Running the DTC.
- The EBCM detects an open in the VES circuit.
- The EBCM detects an open or short in the VES circuit when the feedback current is less than 155 mA while the absolute value of the commanded current is greater than 826 mA for 2.5 seconds.
Action Taken When the DTC Sets
The EBCM disables the variable effort steering (VES) for the duration of the ignition cycle.
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
The vehicle may need to be driven to view non-zero values of the MagnaSteer® Commanded Current and MagnaSteer® Feedback Current on the scan tool.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step uses the scan tool to check the MagnaSteer® Feedback Current parameter.
-
This step checks for an open in the variable effort steering actuator and circuit.
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 scan tool indicate that the MagnaSteer® Feedback Current is greater than the specified value? | 155 mA | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |||||||
3 |
Does the resistance measure within the specified range? | 1.6-3.1 ohms | Go to Step 5 | Go to Step 4 | ||||||
4 | Test both variable effort steering actuator control circuits for a short to ground or short to voltage between the EBCM and the variable effort steering actuator pigtail connector. Refer to Circuit Testing and Wiring Repairs in Wiring System. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 | ||||||
5 | Inspect for poor connections at the harness connector of the variable effort steering actuator. 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 9 | Go to Step 7 | ||||||
6 | Inspect for poor connections at the harness connector of the EBCM. 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 9 | Go to Step 8 | ||||||
7 | Replace the variable effort steering actuator. Refer to Steering Gear Replacement in Power Steering System. Did you complete the repair? | -- | Go to Step 9 | -- | ||||||
8 |
Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will
result in the following conditions:
Replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System. Did you complete the repair? | -- | Go to Step 9 | -- | ||||||
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||
