Steering Controls Schematic Icons
Steering Controls Schematic Icons Icon Icon Definition IMPORTANT: Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. If the wires were covered with shielding, install new shielding. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)
Scheme 1
Scheme 2
Scheme 3
| Callout | Component Name |
|---|---|
| 1 | Telescoping Drive Wheel |
| 2 | Steering Angle Sensor |
| 3 | Turn Signal/Multifunction Switch |
| 4 | Windshield Wiper/Washer Switch Assembly |
| 5 | Steering Wheel Controls Seek Button |
| 6 | Steering Wheel Controls Volume Button |
| 7 | C277 |
| 8 | Horn Switch Connector |
| 9 | Steering Wheel Controls Mute/Source Button -or- Heated Steering Wheel Button (KA1) |
| 10 | Steering Wheel Controls Voice/Preset Button |
| 11 | Heated Steering Wheel |
| 12 | Tilt/Telescope Switch |
| 13 | Tilt Actuator |
| 14 | C202 |
| 15 | Steering Column Lock Control Module (UA2) |
Scheme 4
| Callout | Component Name |
|---|---|
| 1 | Power Steering Rack (LHD) |
| 2 | Variable Effort Steering Actuator (LHD) |
| 3 | Variable Effort Steering Actuator Wiring Harness |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests if the Actuator Commanded and Actuator Feedback Current parameters are within specification in their active state.
- 3: Perform the VES test located under Special Functions. This test may indicate if the VES actuator is mechanically bound.
- 4: This step tests if the resistance of the VES actuator is within specification.
- 7: This step tests the control circuit of the VES actuator for a short to ground.
- 13: Perform the setup procedure after EBCM replacement.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics Connector End View Reference: Steering Controls 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 | |
| 2 | Start the engine. Observe the VES Actuator Commanded Current and VES Actuator Feedback Current Data parameters in the VES data list for the EBCM with a scan tool. Are the VES Actuator Commanded Current and VES Actuator Feedback Current parameters within 0.03 amps of each other and within the specified range? | 0.9-1 amp | Go to Step 3 | Go to Step 4 |
| 3 | Select F2: VES Test with the scan tool. Does the scan tool indicate Test Passed? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 | |
| 4 | Turn OFF the ignition. Disconnect the variable effort steering (VES) actuator harness connector. Measure the resistance of the VES actuator. 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 Wiring Repairs in Wiring Systems. Was a short to ground located? | Go to Step 6 | Go to Step 7 | |
| 6 | 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 | |
| 7 | Test the 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 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 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 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 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 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 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 Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 13 | IMPORTANT: Perform the setup procedure for the EBCM. Replace and reprogram the EBCM. Refer to Control Module References in Computer/Integrating Systems.Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the VES actuator. Refer to Power Steering Gear Replacement in Power Steering System. Did you complete the replacement? | Go to Step 15 | ||
| 15 | Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC. Does DTC C0450 reset? | Go to Step 2 | System OK | |
| IMPORTANT |
|---|
| Perform the setup procedure for the EBCM. |
DTC C0450
Variable Effort Steering System Description and Operation
The variable effort steering (VES) system varies the amount of effort to steer the vehicle as wheel speed changes or lateral acceleration occurs. The electronic brake control module (EBCM) controls an actuator located in the steering rack and pinion. The actuator consists of an electromagnetic coil and a pintle valve which moves in and out of the rack and pinion's input fluid orifice, regulating power steering fluid flow. The EBCM commands current from 0-1 amp to the VES actuator which varies the amount of effort to steer the vehicle. At low speeds, 1 amp of current is commanded to the VES actuator and the pintle valve is fully retracted which provides maximum fluid flow and maximum steering assist for easy turning and parking maneuvers. At high speeds, no current is commanded and the pintle valve moves closer to the orifice, decreasing fluid flow, providing firmer steering, increased road feel, and directional stability. The VES system uses the steering wheel position sensor input to calculate lateral acceleration during abrupt driving maneuvers. The system also uses the antilock brake system (ABS) wheel speed sensor inputs to determine vehicle speed. The EBCM is constantly monitoring these inputs to achieve the desired current to the VES actuator. The EBCM has the ability to detect malfunctions in the VES actuator or the circuits to the actuator. Any malfunctions detected will cause the VES outputs to be disabled and the EBCM will command the driver information center (DIC) to display the SERVICE STEERING SYSTEM warning message via a class 2 serial data circuit.