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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Steering Assist Schematics Connector End View Reference: Steering Assist Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Does the resistance measure within specified range? | 5-10 Ω | Go to Step 3 | Go to Step 10 |
3 | Test the VES actuator and actuator harness for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Was a short to ground located? | -- | Go to Step 4 | Go to Step 5 |
4 | Visually inspect the actuator harness for any cut, chaffed or damaged wires. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
5 | Test the control circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 6 |
6 | Test the control circuit of the VES actuator for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 7 |
7 | Test the return circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 8 |
8 | Test the return circuit of the VES actuator for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
9 | Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
10 | Inspect for poor connections at the harness connector of the VES actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
11 |
Important: Always perform the setup procedure for the EBCM.
Did you complete the replacement? | -- | Go to Step 13 | -- |
12 | Replace the VES actuator. Refer to Steering Gear Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does DTC C0450 reset? | -- | Go to Step 2 | System OK |
