GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2009 🢒 SRX 🢒 Steering 🢒 Power Steering 🢒 DTC C0450

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC C045 00: Steering Assist Control Solenoid/Motor/Actuator Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Variable Effort Steering Actuator Supply Voltage

C0450 00

C0450 00

C0450 00

C0450 00

Variable Effort Steering Actuator Control

C0450 00

C0450 00

C0450 00

C0450 00

Circuit/System Description

The electronic brake control module (EBCM) controls the current through the Variable Effort Steering (VES) actuator located on the steering gear. The current used to control the VES actuator is between 0 and 1 Amp. At low speeds and in parking lot maneuvers the current is applied to the actuator causing the orifice to open increasing fluid flow and reducing the steering effort. At high speeds the orifice is commanded closed by reducing current through the actuator and 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

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

Connector End View Reference:

Component Connector End Views

Description and Operation:

Variable Effort Steering System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference:

Control Module References for scan tool information

Circuit/System Testing

Important: It is recommended that Component Testing is performed before Circuit/System Testing when diagnosing the VES actuator because the module will default and does not supply voltage to the sensor when the DTC is set.

  1. Ignition OFF, disconnect the harness connector at the VES actuator.

    2. Important: In order to ensure correct test results, the J-35616 test lamp must be used to perform the following steps. Failure to use the J-35616 test lamp may result in inaccurate test results and potential misdiagnosis.

  2. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground.
    3. ⇒If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the test lamp between the control circuit terminal A and the control circuit terminal B.
  4. Ignition ON, verify the test lamp briefly illuminates for approximately 1 second, then turns OFF.
    5. ⇒If the test lamp is always ON, test the control circuit terminal B for a short to ground. If the circuit tests normal, replace the EBCM.
    ⇒If the test lamp is always OFF, test the control circuit terminal B for a short to voltage or an open/high resistance. If the circuit tests normal, replace the EBCM.
  5. If all circuits test normal, test or replace the VES actuator.

Component Testing
  1. Ignition OFF, disconnect the VES actuator harness connector terminal A and B.
  2. Measure for 2.5-10 ohms of resistance between the VES actuator terminals.
    3. ⇒ If not 2.5-10 ohms of resistance, replace the VES actuator.
  3. Measure for infinite ohms of resistance between each VES actuator terminals and the VES actuator housing.
    4. ⇒ If less than the specified range, replace the VES actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for EBCM replacement, setup, and programming.
    •  Steering Gear Replacement