GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 GMC C Sierra - 2WD 🢒 Steering 🢒 Rear Wheel Steering 🢒 Wheel Alignment Measurement

Wheel Alignment Measurement With Rear Wheel Steering

Learn Wheel Alignment

After replacement of the handwheel position sensor, rear wheel position sensor or rear wheel steering control module it is necessary to perform the learn wheel alignment procedure.

Alignment Procedure

Steering and vibration complaints are not always the result of improper alignment. One possible cause is wheel and tire imbalance. Another possibility is tire lead due to worn or improperly manufactured tires. Lead is the vehicle deviation from a straight path on a level road without pressure on the steering wheel. Refer to Radial Tire Lead/Pull Correction in Tires and Wheels in order to determine if the vehicle has a tire lead problem.

Before performing any adjustment affecting wheel alignment, perform the following inspections and adjustments in order to ensure correct alignment readings:

    • Inspect the tires for the proper inflation and irregular tire wear. Refer to Tire Inflation Pressure Specifications in Maintenance and Lubrication and Tire Diagnosis - Irregular or Premature Wear in Tires and Wheels.
    • Inspect the runout of the wheels and the tires. Refer to Tire and Wheel Runout Specifications in Vibration Diagnosis and Correction.
    • Inspect the wheel bearings for backlash and excessive play. Refer to Wheel Bearings Diagnosis in Suspension General Diagnosis.
    • Inspect the ball joints and tie rod ends for looseness or wear.
    • Inspect the control arms and stabilizer shaft for looseness or wear.
    • Inspect the steering gear for looseness at the frame. Refer to Fastener Tightening Specifications in Power Steering System.
    • Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Refer to Suspension Strut and Shock Absorber Testing - On Vehicle in Suspension General Diagnosis.
    • Inspect the vehicle trim height. Refer to Trim Height Inspection in Suspension General Diagnosis.
    • Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components.
    • Inspect the fuel level. The fuel tank should be full or the vehicle should have a compensating load added.

Give consideration to excess loads, such as tool boxes, sample cases, etc. If normally carried in the vehicle, these items should remain in the vehicle during alignment adjustments. Give consideration also to the condition of the equipment being used for the alignment. Follow the equipment manufacturer's instructions.

Satisfactory vehicle operation may occur over a wide range of alignment settings. However, if the setting exceeds the service allowable specifications, correct the alignment to the service preferred specifications. Refer to Wheel Alignment Specifications .

Perform the following steps in order to measure the front and rear alignment angles:

  1. Install the alignment equipment according to the manufacturer's instructions.
  2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment.
  3. Measure the alignment angles and record the readings.

    4. Important: When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front alignment angles.

  4. Adjust alignment angles to vehicle specification, if necessary. Refer to Wheel Alignment Specifications then perform the learn alignment procedure.

Learn Wheel Alignment Procedure
  1. Turn ignition to ON position, with the engine ON.
  2. Install the scan tool.
  3. Center the steering wheel.
  4. Lift the rear of the vehicle off the ground ensuring the rear wheels are centered.
  5. Go to the Learn Alignment menu choice in the scan tool. Follow the prompts on the scan tool.

    6. Important: When prompted by the scan tool you must turn the steering wheel a full 90° to the left and a full 90° to the right and then to center and hold. If this step is not done properly then it is possible to cause a false DTC for the steering wheel position sensor.

  6. Press the continue button.
  7. Use the scan tool to clear all rear wheel steering DTC's.

Wheel Alignment Measurement Without Rear Wheel Steering

Steering and vibration complaints are not always the result of improper alignment. One possible cause is wheel and tire imbalance. Another possibility is tire lead due to worn or improperly manufactured tires. Lead is the vehicle deviation from a straight path on a level road without pressure on the steering wheel. Refer to Radial Tire Lead/Pull Correction in Tires and Wheels in order to determine if the vehicle has a tire lead problem.

Before performing any adjustment affecting wheel alignment, perform the following inspections and adjustments in order to ensure correct alignment readings:

    • Inspect the tires for the proper inflation and irregular tire wear. Refer to Tire Inflation Pressure Specifications in Maintenance and Lubrication and Tire Diagnosis - Irregular or Premature Wear in Tires and Wheels.
    • Inspect the runout of the wheels and the tires. Refer to Tire and Wheel Runout Specifications in Vibration Diagnosis and Correction.
    • Inspect the wheel bearings for backlash and excessive play. Refer to Wheel Bearings Diagnosis in Suspension General Diagnosis.
    • Inspect the ball joints and tie rod ends for looseness or wear.
    • Inspect the control arms and stabilizer shaft for looseness or wear.
    • Inspect the steering gear for looseness at the frame. Refer to Fastener Tightening Specifications in Power Steering System.
    • Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Refer to Suspension Strut and Shock Absorber Testing - On Vehicle in Suspension General Diagnosis.
    • Inspect the vehicle trim height. Refer to Trim Height Inspection in Suspension General Diagnosis.
    • Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components.
    • Inspect the fuel level. The fuel tank should be full or the vehicle should have a compensating load added.

Give consideration to excess loads, such as tool boxes, sample cases, etc. If normally carried in the vehicle, these items should remain in the vehicle during alignment adjustments. Give consideration also to the condition of the equipment being used for the alignment. Follow the equipment manufacturer's instructions.

Satisfactory vehicle operation may occur over a wide range of alignment settings. However, if the setting exceeds the service allowable specifications, correct the alignment to the service preferred specifications. Refer to Wheel Alignment Specifications .

Perform the following steps in order to measure the front and rear alignment angles:

  1. Install the alignment equipment according to the manufacturer's instructions.
  2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment.
  3. Measure the alignment angles and record the readings.

    4. Important: When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front alignment angles.

  4. Adjust alignment angles to vehicle specification, if necessary. Refer to Wheel Alignment Specifications .