Diagnostic Starting Point - Variable Effort Steering
Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check will provide the following information
- The identification of the control modules which command the system
- The ability of the control modules to communicate through the serial data circuit
- The identification of any stored diagnostic trouble codes and their status
The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selections | Description |
|---|---|---|
| VES actuator | VES test | The Electronic Brake Control Module (EBCM) can be commanded using the scan tool to perform a self-test varying steering effort from more firm, to less firm, to more firm, then back to normal. |
Scan Tool Output Controls
Scan Tool Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Ignition ON/engine ON/ no vehicle speed present | |||
| ABS Reference Speed | VES Data | Mph | 0 |
| LF Wheel Speed | VES Data | Mph | 0 |
| LR Wheel Speed | VES Data | Mph | 0 |
| RF Wheel Speed | VES Data | Mph | 0 |
| RR Wheel Speed | VES Data | Mph | 0 |
| Ignition Voltage | VES Data | Volts | 13.25 |
| Switched System Battery Voltage | VES Data | Volts | 13.25 |
| VES Failed | VES Data | Yes/No | No |
| VES Indicator Message | VES Data | On/Off | Off |
| VES Commanded Current | VES Data | Amps | 1.00 |
| VES Feedback Current | VES Data | Amps | 1.00 |
Scan Tool Data List
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 in the retracted position. At high speeds, no current is commanded to the actuator and the valve moves closer to the power steering fluid orifice. The EBCM monitors and compares the VES Commanded Current and VES 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
- 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 ignition cycles.
Diagnostic Aids
The vehicle may need to be driven to view full VES Actuator Commanded and Actuator Feedback Data parameters.