Operation CHARM: Car repair manuals for everyone.

Pinpoint Tests

Pinpoint Test A: vibration When the Brakes are Applied

Normal Operation
On a smooth road surface, the vehicle and brake pedal should be free of vibration during normal braking. During moderate to heavy braking, noise from the hydraulic control unit (HCU) and pulsation in the brake pedal can be observed. Pedal pulsation coupled with noise during heavy braking or on loose gravel, bumps, wet or snowy surfaces is acceptable and indicates correct functioning of the ABS. Pedal pulsation or steering wheel nibble when the brakes are applied (frequency is proportioned to the vehicle speed) indicates a concern with a brake or suspension component.

This pinpoint test is intended to diagnose the following:
^ Uneven brake pad wear
^ Brake disc pad transfer
^ Suspension components
^ Brake disc(s)

A1-A6: