Diagnostic Instructions
DTC Descriptor
DTC C0450: Steering Assist Control Solenoid/Motor/Actuator Circuit
Circuit/System Description
The electronic brake control module (EBCM) controls the variable effort steering actuator on the steering gear. At low speeds and parking lot maneuvers the orifice is commanded open increasing fluid flow and reducing the steering effort. At high speeds
the office is commanded closed restricting fluid flow increasing steering effort. The EBCM monitors and compares the Commanded and Feedback Current parameters to detect malfunctions in the VES system.
Conditions for Running the DTC
| • | Ignition voltage between 10.5-17 volts |
| • | Off state test--Initial ignition ON, no engine RPM or vehicle speed present. |
| • | On state test--If off state test passes, engine RPM and vehicle speed present. |
Conditions for Setting the DTC
An open, short to ground or short to voltage in the VES actuator or the circuits to the actuator
Action Taken When the DTC Sets
| • | A DTC C0450 is stored in memory. |
| • | The driver information center (DIC) displays the SERVICE STEERING SYSTEM warning message. |
| • | The VES system is disabled for the remainder of the ignition cycle. |
Conditions for Clearing the DTC
| • | A current DTC will clear when the malfunction is no longer present. |
| • | A history DTC will clear after 100 consecutive ignition cycles with the malfunction no longer present. |
Reference Information
Schematic Reference
Steering Assist Schematics
Connector End View Reference
Description and Operation
Variable Effort Steering System Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Perform the VES Actuator test with a scan tool and turn the steering wheel, the effort should increase and decrease and then back to normal.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the VES actuator.
- Connect a test lamp between the control circuit terminal 2 and ground.
- Cycle the ignition ON and verify the test lamp turns ON then OFF.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the EBCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
- Connect a test lamp between the control circuit terminals 1 and 2.
- Cycle the ignition ON and verify the test lamp turns ON then OFF.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the EBCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the EBCM. |
- Ignition OFF, disconnect the harness connector at the EBCM.
- Test for infinite resistance between the control circuit terminal 28 and ground.
| ⇒ | If not the specified value, test the control circuit for a short to ground. |
- If all circuits test normal, test or replace the VES actuator.
Component Testing
Variable Effort Steering Actuator Test
- Ignition OFF, disconnect the harness connector at the VES actuator.
- Test for 5-10 ohms of resistance between the control terminals 1 and 2.
| ⇒ | If not within the specified range, replace the VES actuator. |
- Test for infinite resistance between each terminal and the VES actuator housing/case.
| ⇒ | If not the specified value, replace the VES actuator. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
