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.
This diagnostic procedure supports the following DTC:
DTC C0450 Steering Assist Control Solenoid/Motor/Actuator Circuit
• | 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. |
An open, short to ground or short to voltage in the VES actuator or the circuits to the actuator.
• | 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. |
• | 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. |
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 |