Circuit Description
The variable effort steering (VES) system uses the electronic brake control module (EBCM) to command current from zero amps to positive 3 amps to an electromagnetic rotary actuator. The VES system uses the antilock brake system (ABS) wheel speed sensor inputs to determine vehicle speed. At low speeds, no current is commanded and steering is assisted by hydraulics only. At high speeds, a positive current is commanded to the VES actuator to create steering resistance. The EBCM monitors and compares commanded and feedback currents to detect malfunctions in the VES actuator or the circuits to the actuator.
Conditions for Running the DTC
| • | The ignition voltage between 10.5-17 volts |
| • | The OFF state test -- initial ignition ON, no engine rpm, or vehicle speed present. |
| • | Then ON state test -- if off state test passes, engine rpm and vehicle speed present. |
Condition 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 C1241 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 the 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 the full commanded and feedback current ranges.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests if the Commanded and Feedback Current parameters are in specified range in there active state.
-
Tests if the VES actuator resistance is within specified range.
-
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 Variable Effort Steering Diagnostic System Check? | -- | Go to Step 2 | |||||||
Does the scan tool indicate that the Magna Steer Commanded and Feedback Current parameters are within 0.05 amps of each other and within the specified range? | 0.60-0.87 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 | ||||||
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 | ||||||
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 | ||||||
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 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 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 variable effort steering actuator. Refer to Steering Gear Replacement in Power Steering System. Did you complete the repair? | -- | Go to Step 14 | -- | ||||||
|
Important: Perform the setup 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 | ||||||
