Hydraulic Control Assembly - Antilock Brakes: Testing and Inspection

Fig. 36 Connecting Scan Tool For HU Test:

Fig. 37 HU Test Results:

Fig. 38 HU Diagnostic Table:

1. Raise and support vehicle.
2. Release parking brake and feel drag force on each wheel. When using the brake force tester, take a reading of the brake drag force.
3. Turn ignition key to Off position and set position scan tool sa shown.
4. Ensure shift lever is in neutral, then start engine. At this time the ABS system will switch to the scan tool mode and the ABS warning lamp will light. When the ABS has been interrupted by the fail safe function, the scan tool actuator testing cannot be used.
5. Use scan tool to force drive the actuator.
6. Turn wheel by hand and check the change in braking force when pedal is applied. When using the brake force tester, depress brake pedal until braking force is at 397 lbs. for the front wheel and 143 lbs. for the rear and ensure braking force changes to the brake drag force measurement from step 2 when the actuator is force driven.
7. results should be as shown.
8. If results are not as specified, correct according to the diagnosis table.