For 1990-2009 cars

Important: Review the system operation in order to familiarize yourself with the system functions. Verify that the brake system is mechanically correct before troubleshooting the warning system. Refer to the following:

• | Brake Warning System Description and Operation

• | Hydraulic Brake System Description and Operation

• | Brake Assist System Description and Operation

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the ABS. Refer to Checking Aftermarket Accessories in Wiring Systems.

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

• | Inspect the master cylinder reservoir for the proper brake fluid level.

• | Inspect the power steering fluid reservoir for the proper power steering fluid level.

### Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Primary Brake Warning Indicator Always On

• | Primary Brake Warning Indicator Inoperative

• | Auxiliary Brake Warning Indicator Always On

• | Auxiliary Brake Warning Indicator Inoperative

• | Brake Booster Pump Inoperative