Circuit Description
The electronic brake control module (EBCM) commands current from 0-1 amp to the 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 commanded and feedback current parameters to detect malfunctions in the VES system.
Conditions for Running the DTC
| • | Ignition voltage between 10.5-17.0 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 C1241 is stored in memory. |
| • | The 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. |
| • | Using a scan tool |
Diagnostic Aids
The vehicle may need to be driven to view full VES Commanded and Feedback Data parameters
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests if the commanded and feedback current parameters are within specification in there active state
-
Perform the VES test located under Special Functions. This test may indicate if the VES actuator is mechanically bound.
-
Tests if the resistance of the VES actuator is within specification.
-
Tests the control circuit of the VES actuator for a short to ground.
-
Perform the set up procedure after EBCM replacement.
Step | Action | Values | 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 display the VES Commanded and Feedback Current Data parameters are within .03 amps of each other and within specified range? | Before VIN 01253 = 0.60 to 0.65 amps After VIN 01253 = .90 amps | Go to Step 3 | Go to Step 4 | |
Using the scan tool, select F2: VES Test. Does the scan tool indicate, Test Passed? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 | |
Does the resistance measure within specified range? | 5.7-7.2 ohms | Go to Step 5 | Go to Step 12 | |
5 | 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 6 | Go to Step 7 |
6 | Visually inspect the actuator harness for any cut, chaffed or damaged wires. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
Test the control circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 8 | |
8 | Test the control circuit of the VES actuator for an open or short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 9 |
9 | Test the return circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and to Wiring Repairs in Wiring Systems. Did you find and correct the condition. | -- | Go to Step 15 | Go to Step 10 |
10 | Test the return circuit of the VES actuator for an open or a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
11 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the VES actuator. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
|
Important: Always perform the setup procedure for the EBCM.
Did you complete the replacement? | -- | Go to Step 15 | -- | |
14 | Replace the VES actuator. Refer to Power Steering Gear Solenoid/Actuator Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
