Initial Inspection and Diagnostic Overview

Most ABS complaints will require a test drive as a part of the diagnostic procedure. The purpose of the test drive is to duplicate the condition.

NOTE: Remember conditions that result in the turning on of the Red BRAKE Warning Lamp may indicate reduced braking ability. The following procedure should be used to test drive an ABS complaint vehicle.

Before test driving a brake complaint vehicle, note whether the Red or Amber Brake Warning Lamp is turned on. If it is the Red Brake Warning Lamp, refer to Brakes. If the ABS Warning lamp was/is on, test drive the vehicle as described below, to verify the complaint. While the ABS Warning Lamp is on, the ABS is not functional. The standard brake system and the ability to stop the car may not be affected if only the ABS Warning Lamp is on.

Discuss with the owner of the vehicle or note any other electrical problems or conditions that may be occurring on the vehicle. They may have an effect on the antilock brake system's function.
1. Turn the key to the off position and then back to the on position. Note whether the ABS Warning Lamp continues to stay on. If it does, refer to the diagnostic manual covering the ITT Teves Mark 20 ABS system for the required test procedures.
2. If the ABS Warning Lamp goes out, shift into gear and drive the car to a speed of 20 kph (12 mph) to complete the ABS start up cycle. If at this time the ABS Warning Lamp goes on refer to the ITT Teves Mark 20 Diagnostic Manual.
3. If the ABS Warning Lamp remains OUT, drive the vehicle a short distance. During this test drive be sure that the vehicle achieves at least 40 mph. Brake to at least one complete stop in an ABS cycle, and again accelerate to 26 mph.
4. If a functional problem with the ABS system is determined while test driving a vehicle, refer to the diagnostic manual covering the ITT Teves Mark 20 ABS system for the required test procedures and proper use of the DRB diagnostic scan tool.

CAUTION: Before road testing a vehicle, be sure that all components are reassembled. During the test drive, do not try to read the DRB screen while in motion. Do not hang the DRB from the rear view mirror or operate it yourself. Have an assistant available to operate the DRB.