Buick Enclave: Specifications, Diagnostic Information and Procedures

SPECIFICATIONS

FASTENER TIGHTENING SPECIFICATIONS

Fastener Tightening Specifications

POWER STEERING PUMP SPECIFICATIONS

Power Steering Pump Specifications

SCHEMATIC WIRING DIAGRAMS

POWER STEERING WIRING SCHEMATICS

NV7

Fig. 1: NV7 Wiring Schematics

COMPONENT LOCATOR

POWER STEERING GEAR DISASSEMBLED VIEW

Disassembled View

DIAGNOSTIC INFORMATION AND PROCEDURES

DIAGNOSTIC CODE INDEX

DTC C0450: STEERING ASSIST CONTROL SOLENOID ACTUATOR

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0450 00

• Steering Assist Control Solenoid Actuator Circuit

DTC C0450 5A

• Steering Assist Control Solenoid Actuator Circuit plausibility failure

Diagnostic Fault Information

Circuit/System Description

The electronic brake control module (EBCM) controls the variable effort steering (VES) actuator on the steering gear. The EBCM controls the actuator using 0 to 1.0 Amp. At 0 mph the EBCM supplies 1.0 Amp to the actuator. As the vehicle speed increases the amperage to the actuator decreases.

Conditions for Running the DTC

• Ignition ON.
• Engine OFF test - Initial ignition ON, no engine RPM or vehicle speed present.
• Engine ON test - If Engine OFF test passes, engine RPM and vehicle speed present.

Conditions for Setting the DTC

A short to voltage, short to ground or open/high resistance is detected on the high control or low control circuit.

Action Taken When the DTC Sets

• The ABS and red brake warning indicators illuminate.
• The driver information center (DIC) displays SERVICE STEERING SYSTEM.
• 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.

Reference Information

Schematic Reference

Power Steering Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Variable Effort Steering System Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Engine running, using a scan tool perform the VES Actuator test. Command the actuator while turning the steering wheel, the effort should increase when commanded between 10-100%.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the VES actuator.

2. Ignition ON, Command the VES actuator to 100% with a scan tool.

3. Test for B+ between the high control circuit terminal 2 and ground.

• If not the specified value, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

4. Connect a DMM, set on the diode setting, between the low control circuit terminal 1 and ground.

5. Command the VES actuator to 0% with a scan tool. The DMM reading should be greater than 2.5 volts or display O.L.

• If less than the specified value, test the low control circuit for a short to voltage or a short to ground. If the circuit tests normal, replace the EBCM.

6. Command the VES actuator to 100% with a scan tool. The DMM reading should be less than 1 volt.

• If greater than the specified range, test the low control circuit for an open/high resistance. If the circuit tests normal, replace the EBCM.

7. If all circuits test normal, test or replace the VES actuator.

Component Testing

1. Ignition OFF, disconnect the harness connector at the VES actuator.

2. Test for 5-10 ohms between the control terminals 1 and 2.

• If not within the specified range, replace the VES actuator.

3. Test for infinite resistance between each terminal and the VES actuator housing/case.

• If not the specified value, replace the VES actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Steering Gear Replacement
• Control Module References for EBCM replacement, setup and programming

SYMPTOMS - POWER STEERING SYSTEM

IMPORTANT: Review the system description and operation in order to familiarize yourself with the system functions. Refer to Power Steering System Description and Operation.

Visual/Physical Inspection

• Inspect for aftermarket devices which could affect the operation of the power steering system.
• Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
• Inspect for leaking power steering components. If necessary, refer to Power Steering Fluid Leaks.
• Verify the power steering reservoir for the proper operating specification. Refer to Checking and Adding Power Steering Fluid.
• Inspect the power steering fluid for the following indications of contamination:
  • Milky fluid - water
  • Brown fluid - burnt
  • Debris in fluid - plastic or dirt
• If necessary, flush the power steering system. Refer to Power Steering System Flushing.

Symptoms List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• Power Steering Fluid Leaks
• Rattle, Clunk or Shudder Noise from the Power Steering System
• Whine or Growl Noise from the Power Steering System
• Steering Effort Hard in One or Both Directions
• Steering Effort Too Easy in One or Both Directions

POWER STEERING SYSTEM TEST

Rack and Pinion System

Fig. 3: Testing Rack and Pinion System Pressures

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5

This step tests the system for restrictions.

7

This step tests the following components for the following conditions:

• The pump for internal leaks
• The power steering pipes for kinks

8

This step tests the ability of the pump to regulate flow at maximum pressure.

10

This step tests the ability of the pump to regulate flow under normal operating conditions.

12

This step tests the internal components of the pump and the gear.

Power Steering System Test

POWER STEERING FLUID LEAKS

Special Tools

• GE-28431-6 Fluorescent Dye

For equivalent regional tools, refer to Special Tools.

NOTE:

• If fluid is found on a manual steering gear or on an electronic power steering gear, do not replace steering gear. Vehicles equipped with these systems do not use hydraulic power steering fluid. The fluid may be assembly fluid or another system fluid.
• Clean the components and identify the sources of the leaks before attempting to repair or replace any power steering components. Clearly mark all locations of leaks with paint, marker or equivalent for warranty identification and engineering root cause analysis.

Some customers may comment on a fluid LEAK or NOISY power steering pump. Upon inspection, the technician may find power steering fluid leaking from the hydraulic power steering system. Use the following inspection procedure in order to diagnose the source of the leak and take appropriate action to correct the condition.

1. Inspect the fluid level in the power steering fluid reservoir. Refer to Checking and Adding Power Steering Fluid. If the fluid level is NOT low, a careful analysis of the condition is necessary to confirm that the type of fluid is actually power steering fluid.

2. Visually inspect the power steering system and components where the fluid has accumulated.

3. Use a clean towel or a rag in order to completely clean off all residual fluid from the power steering components.

CAUTION: Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings.

4. Add 30 cc (1 oz) of GE-28431-6 dye to the power steering fluid.

5. Start the vehicle and warm the steering system by turning to the left steering stop and to the right steering stop 10 times with the weight of the vehicle on the front tires.

6. Turn vehicle engine OFF.

7. Shine a black light on the area where the residual fluid accumulated. Identify the sources of the leaks.

8. Mark all locations of leaks with paint, marker or equivalent.

9. Repair or replace all affected components.

RATTLE, CLUNK OR SHUDDER NOISE FROM THE POWER STEERING SYSTEM

Rattle, Clunk or Shudder Noise from the Power Steering System

WHINE OR GROWL NOISE FROM THE POWER STEERING SYSTEM

Whine or Growl Noise from the Power Steering System

STEERING EFFORT TOO EASY IN ONE OR BOTH DIRECTIONS

Steering Effort Too Easy in One or Both Directions

STEERING EFFORT HARD IN ONE OR BOTH DIRECTIONS

Steering Effort Hard in One or Both Directions

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