ASE A4 Suspension and SteeringWheel Alignment Diagnosis, Adjustment, and RepairMedium
A technician is performing a four-wheel alignment. The alignment machine has just completed the 'runout compensation' procedure. What is the PRIMARY purpose of this procedure?
- ATo adjust the steering wheel position before toe adjustments.
- BTo measure the vehicle's ride height at each corner.
- CTo calibrate the alignment machine's sensors to a known standard.
- DTo compensate for any inaccuracies caused by bent wheels or improperly mounted sensors.
Show answer & explanationAnswer & explanation
Correct answer: D. To compensate for any inaccuracies caused by bent wheels or improperly mounted sensors.
Runout compensation is performed to account for any imperfections in the wheels themselves (e.g., a bent wheel) or how the alignment sensors are mounted, ensuring these mechanical inaccuracies do not affect the alignment angle measurements.
Why the other options are wrong
- A. Adjusting steering wheel position is done later, before front toe adjustments, and is unrelated to runout compensation.
- B. Ride height measurement is a pre-alignment check, not the purpose of runout compensation.
- C. Machine calibration is a separate, periodic maintenance task, not part of runout compensation during an alignment.
Runout Compensation
A procedure performed during alignment setup to eliminate measurement errors caused by wheel runout or improper sensor mounting.
- Crucial for measurement accuracy.
- Involves rotating the wheels.
- Compensates for non-concentricity.
Memory trick: Runout compensation ensures a true spin.