C0450

DTC C0450

Circuit 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 Commanded and Feedback Current parameters to detect malfunctions in the VES system.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0450 Steering Assist Control Solenoid/Motor/Actuator Circuit

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.

Diagnostic Aids

The vehicle may need to be driven to view full VES Commanded and Feedback Data parameters

Test Description

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests if the Commanded and Feedback Current parameters are within specification in their active state.
3. Perform the VES test located under Special Functions. This test may indicate if the VES actuator is mechanically bound.
4. This step tests if the resistance of the VES actuator is within specification.
7. This step tests the control circuit of the VES actuator for a short to ground.
13. Perform the setup procedure after EBCM replacement.

Step 1 - Step 8:

Step 9 - Step 15: