Pinpoint Tests

Suspension System

Pinpoint Tests

Pinpoint Test A: Vehicle Drifts/Pulls

This pinpoint test is intended to diagnose the following:

- Unevenly loaded vehicle

- Tire pressure

- Tire forces

- Brake drag

- Incorrect vehicle alignment

- Steering system

PINPOINT TEST A : VEHICLE DRIFTS/PULLS

NOTE: This vehicle is equipped with Electronic Power Assist Steering (EPAS). EPAS (Electronic Power Assist Steering) equipped vehicles have a control strategy which will reduce pull at the steering wheel as perceived by the customer: The system will start compensating when vehicle speeds exceed 25 mph (40 kph) and the vehicle is traveling straight ahead. The system will compensate on any road crown condition; however, some amount of pull will be present during, and shortly after, quick lane transitions. After driving in a given straight lane with your hand on the wheel for thirty seconds, you can begin to assess the pull condition.
The system does not compensate when turning and at low speeds. For the system to compensate, the driver must have their hand on the wheel.

A1 CHECK FOR UNEVENLY LOADED VEHICLE

- Visually check the vehicle for an uneven loading condition.

Is the vehicle unevenly loaded?

Yes
ADVISE the customer of uneven loading condition.

No
GO to A2.

A2 CHECK THE TIRE PRESSURES AND TIRE CONDITIONS

- Check the tire pressures. Refer to the Vehicle Certification (VC) label located on the driver door jamb. Check the tires for uneven/abnormal wear. Refer to Diagnosis and Testing - Wheels and Tires Testing and Inspection.

Are the tire pressures and tire conditions OK?

Yes
GO to A3.

No
ADJUST the tire pressures to the specified pressure or INSTALL new tires as necessary.

A3 ISOLATE TIRE DRIFT/PULL CONDITION

- NOTE: It is important to determine if tire forces are the cause of a drift/pull condition. Changing the position of the wheel and tire assemblies on the vehicle may correct a pull/drift condition. A tire or tires that are causing a drift/pull should not be removed from service unless it has been determined that the tire(s) are worn beyond specification. Refer to Diagnosis and Testing - Wheels and Tires Testing and Inspection.

Cross the front wheel and tire assemblies from left-to-right.

Does the vehicle drift/pull?

Yes
If the vehicle drifts/pulls in the opposite direction, tire forces are causing the drift/pull. ROTATE the wheel and tire assemblies from front-to-rear. REFER to Wheels and Tires.
If the vehicle drifts/pulls in the same direction, GO to A4.

No
Tire forces were causing the drift/pull and the concern has been corrected.

A4 CHECK FOR BRAKE DRAG

- Spin all 4 wheel and tire assemblies by hand and check for brake drag.

Do the wheels spin freely?

Yes
GO to A5.

No
REFER to Brakes and Traction Control to diagnose brake drag condition.

A5 CHECK THE WHEEL ALIGNMENT

- Using alignment equipment and the manufacturer's instructions, check the wheel alignment.

Is the wheel alignment out of specification?

Yes
ADJUST the alignment as necessary. REFER to General Procedures.

No
REFER to Steering to diagnose steering system drift/pull/wander condition.