C0450

DTC C0450

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



DTC Descriptors
DTC C0450
- Steering Assist Control Solenoid/Motor/Actuator Circuit




Circuit/System Description

The electronic brake control module (EBCM) commands current from 0-1 amp to the variable effort steering (VES) actuator, depending on vehicle speed. At low speeds, 1 amp of current is commanded to the actuator and the actuator valve is fully closed. A speed increases, less current is commanded to the actuator and the valve opens, allowing pressure to bleed off through a power steering fluid orifice. The EBCM monitors and compares the VES Actuator Commanded and VES Actuator Feedback Signal 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

The EBCM detects an open, short to ground, or short to voltage in the VES actuator or the actuator circuits.


Action Taken When the DTC Sets

* DTC C0450 is stored in memory.
* The driver information center (DIC) displays the SERVICE POWER STEERING SYSTEM warning message.
* The VES system is disabled for the remainder of the ignition cycle.



Conditions for Clearing the DTC

* The condition for setting the DTC is no longer present.
* The 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 full VES Actuator Commanded and Actuator Feedback Data parameters.


Reference Information:
Schematic Reference:

Power Steering Schematics (Electrical Diagrams)
Connector End View Reference:

Component Connector End Views (Connector Views)
Description and Operation:

Variable Effort Steering System Description and Operation (Variable Effort Steering System Description and Operation)
Electrical Information Reference:

* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Circuit Testing (Component Tests and General Diagnostics)

Scan Tool Reference:

Control Module References (Programming and Relearning)


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 go back to normal.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the VES actuator.
2. Ignition ON, verify that a test lamp illuminates between the high effort control circuit terminal 1 and ground.

• If the test lamp does not illuminate, test the high effort control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

3. Verify that a test lamp illuminates between control the low effort control circuit terminal 2 and ground.

• If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

4. If all circuits test normal, test or replace the VES actuator.



Component Testing

1. Ignition OFF, disconnect the VES actuator harness connector.
2. Measure for 5-10 ohms of resistance between the VES actuator terminals 1 and 2.

• If the resistance is outside the specified range, replace the VES actuator.

3. Measure for infinite ohms of resistance between each VES actuator terminal and the VES actuator housing.

• If less than the specified range, replace the VES actuator.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming.
* Steering Gear Replacement (Left Hand Drive) (Service and Repair)Steering Gear Replacement (Right Hand Drive) (Service and Repair)