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 |
Steering Controls Connector End Views
Steering Angle Sensor Connector End Connector Part Information OEM: 12064978 Service: 12125678 6-Way F Micro-Pack 100 Series (GY) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function 1 GY/BK 1337 5 Volt Reference 2 L-GN/BK 1338 Low Reference 3-4 - - Not Used 5 L-GN 1763 Steering Wheel Position Signal A 6 L-BU 1764 Steering Wheel Position Signal B
Variable Effort Steering Actuator Connector End (w/NV7) Connector Part Information OEM: 963040-1 Service: 2-Way F Junior Power Timer Series (BU) Pin Wire Color Circuit No. Function 1 GY 1787 Variable Effort Steering Actuator High Effort Control 2 WH 345 Variable Effort Steering Actuator Low Effort Control
Variable Effort Steering Actuator Connector End (w/o NV7) Connector Part Information OEM: E3550 Service: 2-Way F Sealed 1.5 mm (BK) Pin Wire Color Circuit No. Function 1 GY 1787 Variable Effort Steering Actuator High Effort Control 2 WH 345 Variable Effort Steering Actuator Low Effort Control
Diagnostic Starting Point - Variable Effort Steering
Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check will provide the following information
- The identification of the control modules which command the system
- The ability of the control modules to communicate through the serial data circuit
- The identification of any stored diagnostic trouble codes and their status
The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selections | Description |
|---|---|---|
| VES actuator | VES test | The Electronic Brake Control Module (EBCM) can be commanded using the scan tool to perform a self-test varying steering effort from more firm, to less firm, to more firm, then back to normal. |
Scan Tool Output Controls
Scan Tool Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Ignition ON/engine ON/ no vehicle speed present | |||
| ABS Reference Speed | VES Data | Mph | 0 |
| LF Wheel Speed | VES Data | Mph | 0 |
| LR Wheel Speed | VES Data | Mph | 0 |
| RF Wheel Speed | VES Data | Mph | 0 |
| RR Wheel Speed | VES Data | Mph | 0 |
| Ignition Voltage | VES Data | Volts | 13.25 |
| Switched System Battery Voltage | VES Data | Volts | 13.25 |
| VES Failed | VES Data | Yes/No | No |
| VES Indicator Message | VES Data | On/Off | Off |
| VES Commanded Current | VES Data | Amps | 1.00 |
| VES Feedback Current | VES Data | Amps | 1.00 |
Scan Tool Data List
Circuit Description
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 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 VES Commanded Current and VES Feedback Current parameters to detect malfunctions in the VES system.
DTC Descriptor
This diagnostic procedure supports the following DTC
DTC C0450 Steering Assist Control Solenoid/Motor/Actuator Circuit
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
- 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.
Conditions for Clearing the DTC
- A current DTC will clear when the malfunction is no longer present.
- A history DTC will clear after 100 ignition cycles.
Diagnostic Aids
The vehicle may need to be driven to view full VES Actuator Commanded and Actuator Feedback Data parameters.
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.
See also:
• Diagnostic System Check - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Testing for Short to Ground
• Wiring Repairs
• Circuit Testing
• Connector Repairs
• Control Module References
• Power Steering Gear Replacement
• Steering Controls Schematics
• Steering Controls Connector End Views