System Performance Test Procedures

Step # 1: Verify operation of the ABS warning light. Turn the ignition ON without starting the engine. The ABS warning light should light up and stay on. Start the engine. The ABS warning light should remain ON while the starter is operating. One or two seconds after the engine starts, the ABS warning light should go OFF.

Step # 2: Road test the vehicle. Speed should exceed 20 mph for more than 30 seconds in order for all self diagnostic procedures to occur. When speed first reaches 4-6 mph, listen for the ABS self test. The whine of the motor and the thump or groan from the HU indicates that the self test is taking place. The ABS warning light should not come on during this period. Verify normal brake system operation. Then find a suitable place to test the ABS by applying the brake hard enough to cause the system to operate. The vibration or pulsation of the operating system should be heard and in some cases the tire chirp as the system alternately applies and releases the brake on the wheel that is tending to lock up.

Step # 3: Connect the scan tool to verify that no trouble codes have been set during the road test.

Step # 4: Visually examine the outside of the Hydraulic Unit to verify that there are no hydraulic fluid leaks in the unit or its connections. Verify that there are no hydraulic fluid leaks in any part of the braking system.






ANTI-LOCK BRAKE SYSTEM DIAGNOSIS TOOL APPLICATIONS






SPECIAL SCAN TOOL INSTRUCTIONS FOR VEHICLES LISTED IN TABLE

NOTE: If working on a vehicle that uses the cigar lighter adapter to power the scan tool, hook the scan tool directly to the battery. Otherwise the power to the scan tool is interrupted when the ignition key is cycled.

1. At the main menu, choose "1. System Select".
2. At the System Select menu, choose "ABS".
3. The scan tool displays a screen starting with "Communication failed....".
4. Push the ">" key.
5. Push the "YES" key to view various systems.
6. Make the appropriate vehicle selection.
7. Turn the ignition OFF and then ON again once.
8. Proceed according to the scan tool instructions.

Points To Remember:
- During a test drive, if the scan tool is left connected, the ABS is disabled and the ECU will not set a code!
- ECU codes are passed to the MUT only AFTER a test drive at least 20 mph for more than 30 seconds. Even though the ABS light may go on during the test, some codes will not be available to the MUT until the drive is done and the vehicle has stopped.

To erase the codes displayed after taking steps 1-8,:

1. While still in the ABS menu screen, choose "Actuator Tests".
2. Use up/down arrow keys to find 07. Erase Diag.
3. Push "Y" (The screen will begin flashing).
4. When the flashing stops, push "C" once.
5. Turn off the ignition.
6. Unplug the scan tool.
7. Test drive the vehicle over 20 mph for more than 60 seconds so the ABS ECU can perform all self diagnostic checks.