Initial Inspection and Diagnostic Overview

WARNING: BRAKE FLUID CONTAINS POLYGLYCOL ETHERS AND POLYGLYCOLS. AVOID CONTACT WITH EYES. WASH HANDS THOROUGHLY AFTER HANDLING. IF BRAKE FLUID CONTACTS EYES, FLUSH EYES WITH RUNNING WATER FOR 15 MINUTES. GET MEDICAL ATTENTION IF IRRITATION PERSISTS. IF TAKEN INTERNALLY, DRINK WATER AND INDUCE VOMITING. GET MEDICAL ATTENTION IMMEDIATELY.

CAUTION: Brake fluid is harmful to painted and plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.

NOTE:
- Always check the fluid level in the brake master cylinder before performing the test procedures. If the fluid level is not at the MAX line, add High Performance DOT-3 Motor Vehicle Brake Fluid.
- The hydraulic anti-lock actuator assembly is not serviceable nor can it be pressure checked. If any of its components fail, it must be replaced as a complete unit.
- Radio Frequency Interference (RFI) can cause false Diagnostic Trouble Codes (DTCs) to be generated if aftermarket electrical work has been done.
- Problems in other areas may affect the operation of the anti-lock brake control system. Those areas include:
- Steering and suspension.
- Tire integrity and air pressure.
- Wheel bearings.
- Brake components that are common to all brake systems.

ROAD TEST
General Guidelines

NOTE:
- Do not alter the vehicle prior to the Road Test. Any change may affect the intensity of the driver's concerns and prevent an accurate diagnosis. The ability of the test driver to make valid comparisons and detect performance deficiencies will depend on training, experience and product knowledge.
- The test driver should have a thorough knowledge of brake system operation and accepted general performance guidelines in order to make valid comparisons and detect performance problems. Perform a Road Test to compare the vehicle's braking performance with the driver's concerns. The Road Test should be performed on a smooth and level road. For optimum traction and control during the road test, avoid gravel, crowned or uneven road surfaces.

Begin the Road Test with a general brake performance check. This includes: Testing the brakes at different speeds using light, moderate, and heavy pedal pressure. Being alert to noises, vibrations, and pulling or drifting conditions. Avoid locking the brakes and skidding the tires. Locked brakes are not an indicator of braking efficiency.

Drive Cycle Test
The Drive Cycle Test will serve three possible purposes:
- Symptom Evaluation Drive. When a vehicle is brought in, the customer may only have a general concern about the way the vehicle is braking. In these situations there may not be a clear system concern to troubleshoot. This drive test is designed to produce common system concern symptoms. Once a symptom is found, a symptom troubleshooting procedure can be followed to service the vehicle.
- Concern Repeatability Drive. This drive procedure is used to verify concern repeatability prior to continuing the diagnostic procedures detailed in the pinpoint tests. After clearing all retrieved DTCs, the vehicle should be driven in an attempt to repeat the concern. Following this drive, retrieve all DTCs and return to the pinpoint test.
- Service Verification Drive. This drive procedure can be used after all service. Because the anti-lock brake control module is unable to detect some system concerns until the vehicle is being driven in a certain way, this drive test can be helpful in developing further confidence in system operation before delivery to the customer.

VISUAL INSPECTION
Visually inspect for the following signs of mechanical and electrical damage:

Mechanical
- Insufficient brake fluid
- Damaged brake anti-lock sensor indicator(s)
- Damaged hydraulic anti-lock actuator
- Damaged hydraulic system piping
- Damaged wheel bearings

Electrical
- Blown fuse:
- 60A ABS
- 15A HEGO
- 10A METER
- 15A METER (Wagons Only)
- 15A STOP
- Damaged wiring harness
- Loose or corroded connection(s)
- Damaged anti-lock brake control module
- Damaged stoplamp switch
- Blown anti-lock brake warning indicator miniature bulb
- Damaged brake anti-lock sensor(s)
- Damaged hydraulic anti-lock actuator
- Damaged anti-lock relay

If the fault is not visually evident, verify the symptom; refer to the System Pre-Check. Reading and Clearing Diagnostic Trouble Codes