5 - 116 ANTI-LOCK 6 BRAKE SYSTEM
judged to be a problem due to not being familiar with the ABS system. These conditions can be recognized without performing extensive diagnostic work. Given adequate understanding of the operating principles and performance characteristics of the ABS system. See Section 1 of this manual to familiarize yourself with the operating principles of the ABS system.
DEFINITIONS
Several abbreviations are used in this manual. They are presented here for reference.
²CABÐController Anti-Lock Brake
²ABSÐAnti-Lock Brake System
²PSIÐPounds per Square Inch (pressure)
²WSSÐWheel Speed Sensor
ABS COMPUTER SYSTEM SERVICE PRECAUTIONS
The ABS system uses an electronic control module, the (CAB). This module is designed to withstand normal current draws associated with vehicle operation. However care must be taken to avoid overloading the (CAB) circuits. In testing for open or short circuits, do not ground or apply voltage to any of the circuits unless instructed to do so by the appropriate diagnostic procedure. These circuits should only be tested using a high impedance multimeter, special tools or the DRB II tester as described in this section. Power should never be removed or applied to any control module with the ignition in the ON position. Before removing or connecting battery cables, fuses, or connectors, always turn the ignition to the OFF position.
ABS GENERAL SERVICE PRECAUTIONS
TEST DRIVING ABS COMPLAINT VEHICLES
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.
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 the standard brake, Control Valves Section in the brake group of this manual. If the Amber Anti-Lock Warning light was/is on, read record and erase the fault. While the Amber ABS Warning Lamp is on the ABS system is not functional. When the Amber AntiLock Warning Lamp is on only the Anti-Lock function of the brake system if affected. The standard brake system and the ability to stop the car is not be affected if only the Amber Anti-Lock Warning Lamp is on.
Ä
(1)Turn the key to the off position and then back to the on position. Note whether the Amber ABS Warning Lamp continues to stay on. If it does refer to the 1992 M.Y. Bendix Anti-Lock 6 Diagnostic Manual for the required test procedures.
(2)If the Amber ABS Warning Lamp goes out, shift into gear and drive the car to a speed of 5 mph to complete the ABS start up cycle. If at this time the Amber ABS Warning Lamp goes on refer to the Bendix Anti-Lock 6 Diagnostic Manual.
(3)If the Amber ABS Warning Lamp remains OUT, drive the vehicle a short distance. During this test drive be sure that the vehicle achieves at least 25 mph. Brake to at least one complete stop and again accelerate to 25 mph.
(4)If a functional problem with the A.B.S. system is determined while test driving a vehicle. Refer to the Bendix Anti-Lock 6 Diagnostics Manual for required test procedures and proper use of the DRB II tester.
ABS BRAKE SYSTEM ON VEHICLE SERVICE
The following are general precautions which should be observed when servicing and diagnosing the ABS system and/or other vehicle systems. Failure to observe these precautions may result in ABS system damage.
(1)If welding work is to be performed on a vehicle using an arc welder, the (CAB) should be disconnected before the welding operation begins.
(2)The (CAB) and modulator assembly 10 way connector should never be connected or disconnected with the ignition in the on position.
(3)Some components of the ABS system are not serviced separately and must be serviced as complete assemblies. Do not disassemble any component which is designated as non-serviceable.
CAUTION: Brake fluid will damage painted surfaces. If brake fluid is spilled on any painted surfaces, wash off with water immediately.
WHEEL SPEED SENSOR CABLES
Proper installation of the Wheel Speed Sensor Cables is critical to continued system operation. Be sure that cables are installed, routed and clipped properly. Failure to install speed sensor cables as shown in the on car service section of this manual. May result in contact with moving parts or over extension of cables, resulting in component failure and an open circuit.