MODULE-ANTILOCK BRAKE
DESCRIPTION
The Antilock Brake Module (ABM) is mounted to the Hydraulic Control Unit (HCU) and operates the ABS system.
OPERATION
The ABM voltage source is through the ignition switch in the RUN position. The ABM contains dual microprocessors. A logic block in each microprocessor receives identical sensor signals. These signals are processed and compared simultaneously. The ABM contains a self check program that illuminates the ABS warning light when a system fault is detected. Faults are stored in a diagnostic program memory and are accessible with the scan tool. ABS faults remain in memory until cleared, or until after the vehicle is started approximately 50 times. Stored faults are not erased if the battery is disconnected.
REMOVAL
1. Remove the master cylinder (Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/MASTER CYLINDER - REMOVAL).
2. Install prop rod on the brake pedal to keep pressure on the brake system.
3. Remove negative battery cable from the battery.
4. Pull up on the ABM harness connector release (1) and remove connector (2).
5. Remove brake lines (2) from the HCU (4).
6. Remove HCU/ABM mounting nuts and bolt (4) and remove HCU (2) / ABM (3) as an assembly.
7. Remove the ABM from the HCU.
INSTALLATION
NOTE: If the ABM is being replaced with a new ABM is must be reprogrammed with the use of a scan tool.
1. Install the ABM on the HCU and tighten then screws to 2 N·m (16 in. lbs.).
2. Install HCU/ABM (2&3) on the mounting studs (4).
3. Install mounting nuts and bolt (4). Tighten to 11.5 N·m (102 in. lbs.).
4. Install brake lines (2) to the HCU (4) and tighten to 19 N·m (170 in. lbs.).
5. Install wiring harness connector (2) to the ABM and push down on the release (1) to secure the connector.
6. Install the master cylinder (Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/MASTER CYLINDER - INSTALLATION).
7. Install negative battery cable to the battery.
8. Bleed ABS brake system (Refer to 5 - BRAKES - STANDARD PROCEDURE).