Wheel Alignment Measurement w/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/pull is defined as follows: at a constant
highway speed on a typical straight road, lead/pull is the amount of effort required
at the steering wheel to maintain the vehicles straight path. 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 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 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:
- Install the alignment equipment according to the manufacturer's instructions.
- Jounce the front and the rear bumpers 3 times prior to checking
the wheel alignment.
- Measure the alignment angles and record the readings.
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.
- Adjust alignment angles to vehicle specification, if necessary. Refer to
Wheel Alignment Specifications
then perform the learn
alignment procedure.
Learn Wheel Alignment Procedure
- Turn ignition to ON position, with the engine ON.
- Install the scan tool.
- Center the steering wheel.
- Lift the rear of the vehicle off the ground ensuring the rear wheels are
centered.
- Go to the Learn Alignment menu choice in the scan tool. Follow the prompts
on the scan tool.
Important: When prompted by the scan tool you must turn
the steering wheel a full 90 degrees to the left and a full 90 degrees
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.
- Press the continue button.
- Use the scan tool to clear all rear wheel steering DTCs.
Wheel Alignment Measurement w/o 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/pull is defined as follows: at a constant
highway speed on a typical straight road, lead/pull is the amount of effort required
at the steering wheel to maintain the vehicles straight path. 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 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 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:
- Install the alignment equipment according to the manufacturer's instructions.
- Jounce the front and the rear bumpers 3 times prior to checking
the wheel alignment.
- Measure the alignment angles and record the readings.
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.
- Adjust alignment angles to vehicle specification, if necessary. Refer to
Wheel Alignment Specifications
.