Component Description

ABS Module 

The ABS module is attached directly to the HCU and is not available separately for service. The ABS module is the ECU for all of the ABS and stability control systems, parking brake and electric brake boost. The ABS module monitors all sensor inputs and all CAN messages relating to ABS, stability control and driver input, then directly controls the solenoid valves and the hydraulic pump motor in the HCU. When an ABS, EBB or stability control system fault has been corrected or a new component has been installed, the ABS module must be programmed or calibrated using a diagnostic scan tool. The calibration procedure is required for the stability control sensors to learn the zero-position of the vehicle. The calibration procedure requires the vehicle to be on a level surface and not moving. The calibration procedure (IVD Initialization) is carried out using a diagnostic scan tool. The vehicle must also be driven over 20 km/h (12 mph) for at least 1 minute on a fairly straight road which allows the ABS module to find the steering angle center.

Hydraulic Control Unit 

The HCU contains the Linear actuator, solenoid valves, the hydraulic pump motor and the pressure sensors used by the ABS for EBB, ABS and the various stability control systems. The ABS module and the HCU are attached directly together and not serviced separately. The brake fluid reservoir is the only serviceable component on the HCU assy. A new HCU comes with a new ABS module. When a new HCU assembly is installed, it must be programmed with the vehicle configuration information and programmed with the latest level of module software. These procedures are carried out using a diagnostic scan tool. Follow all scan tool instructions. For additional information, refer to: Module Programming

When an ABS, stability control system or EBB fault has been corrected or a new component has been installed, the ABS module must be calibrated. The calibration procedure is required for the stability control sensors to learn the zero-position of the vehicle. The calibration procedure requires the vehicle to be on a level surface and not moving. The calibration procedure (IVD Initialization) is carried out using a diagnostic scan tool. The vehicle must also be driven over 20 km/h (12 mph) for at least 1 minute on a fairly straight road which allows the ABS module to find the steering angle center.

This system does not incorporate a traditional master cylinder as a separate component. The master cylinder is now part of the HCU. All brake system function is controlled by the ABS module / HCU assy. The brake fluid reservoir is the only serviceable component on the HCU assy.

Linear Actuator 

The Linear Actuator controls all pressure within the brake system. It is an integral component to the HCU and cannot be serviced separately.