Circuit Description
The variable effort steering (VES) system uses the electronic brake control module (EBCM) to control current to a bi-directional electromagnetic rotary actuator. The EBCM commands current from negative 3 amps to positive 3 amps to the actuator. At low speeds, less than approximately 24 km/h (15 mph), negative three amps of current is commanded, providing maximum assist to steering. As speed increases, increased (more positive) current is commanded, reaching zero amps at approximately 96 km/h (60 mph). The EBCM commands positive current only during steering input at higher speeds, based on the above inputs and the vehicle calibration, which creates steering resistance.
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 DIC may display the SERVICE STEERING SYS warning message. |
| • | The VES system is disabled. |
Conditions for Clearing the DTC
| • | A current DTC will clear when malfunction is no longer present. |
| • | A history DTC will clear after 100 consecutive ignition cycles with no malfunction present. |
| • | Using the scan tool. |
Diagnostic Aids
The vehicle needs to be driven to view full commanded and feedback current ranges on the scan tool.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests if the Commanded and Feedback Current parameters are at the specified value in their active state.
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Tests if the resistance of the VES actuator is in the specified range.
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Tests the high effort control circuit for an open or short to voltage.
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Tests the low effort control circuit for a short to ground.
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Tests for poor connections at the VES actuator harness connector.
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Perform the setup procedure after EBCM replacement.
Step | Action | Value(s) | 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 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||||||||||||
Does the scan tool indicate that the VES Actuator Commanded and the VES Actuator Feedback parameters are within .05 amps of each other and at the specified value? | -3.00 A | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |||||||||||||||||
Does the resistance measure within the specified range? | 1.6-3.1 ohms | Go to Step 4 | Go to Step 10 | |||||||||||||||||
4 | Test the VES actuator and actuator harness for a short to ground. Refer to Testing for Short to Ground and to Wiring Repairs in Wiring Systems. Was a short to ground located? | -- | Go to Step 5 | Go to Step 6 | ||||||||||||||||
5 | Visually inspect the actuator harness for any cut, chaffed or damaged wires. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 | ||||||||||||||||
6 | Test the high effort control circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 7 | ||||||||||||||||
Test the high effort control circuit of the VES actuator for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 8 | |||||||||||||||||
Test the low effort control circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 9 | |||||||||||||||||
9 | Test the low effort control circuit of the VES actuator for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 | ||||||||||||||||
Inspect for poor connections at the harness connector of the VES actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 | |||||||||||||||||
11 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 | ||||||||||||||||
12 | Replace the VES actuator. Refer to Steering Gear Replacement in Power Steering System. Did you complete the repair? | -- | Go to Step 14 | -- | ||||||||||||||||
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Important: Perform the set up procedure for the EBCM.
An unprogrammed EBCM will result in the following conditions:
Replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System. Did you complete the repair? | -- | Go to Step 14 | -- | |||||||||||||||||
14 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||||||||||||
