GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Check the master cylinder fluid level.

Master cylinder fluid level between ADD and FULL.

Master Cylinder Reservoir Low

2

Perform Vacuum Booster Functional Test. Refer to Vacuum Booster Diagnosis .

Brake pedal falls away and then pushes back.

Accumulator Leak-Down System Not Holding Charge

3

  1. Turn ignition OFF.
  2. Park brake not applied.
  3. Start the engine.

Brake warning indicator illuminates briefly (approximately 5 seconds).

    • Brake Warning Indicator Always ON
    • Brake Warning Indicator Inoperative

4

With the vehicle in PARK, perform Brake Pedal Travel Test. Refer to Brake Pedal Travel .

    • Brake pedal moves steadily towards floor, approximately 2-3 in.
    • Brake pedal stops and is firm against the pressure (Hydraulic brake booster may hiss or clunk/click/clatter with high brake pedal effort).
    • Brake Pedal Excessive Travel
    • Brake Pedal Travel Gradually Increases
    • Brake Pedal Excessive Effort
    • Hydraulic Brake Booster Noisy

5

Release the brake pedal.

Brake pedal returns to normal height.

Brake Pedal Slow Return

6

  1. Press the brake pedal.
  2. Shift vehicle into DRIVE.
  3. Perform Brake System Test. Refer to Brake System Testing .
    • Braking action starts after applying the brakes.
    • Brakes do not grab - brake pedal does not vibrate.
    • Vehicle stops without excessive pedal effort.
    • Vehicle stops without pulling to one side.
    • Front and rear brakes apply evenly.
    • Vehicle stops without noise coming from the brakes.
    • Vehicle stops without noise coming from the hydraulic booster.
    • Brakes do not drag after releasing the brake pedal.
    • Brakes do not make noise while driving.
    • Brake System Slow Response
    • Brake Pedal Excessive Effort
    • Braking Uneven - Side to Side
    • Braking Uneven - Front to Rear
    • Brake System Noise with Brakes Applied
    • Brake System Groan at End of Stop
    • Hydraulic Brake Booster Noisy
    • Brakes Drag
    • Brakes System Noise with Brakes Not Applied

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.