Control module and ABS hydraulic modulator

The ABS control module is mounted on the hydraulic modulator in the engine compartment.

It is supplied with power via two fuses and connected to ground by a ground terminal.

There are diagnostics for the valve coils.

There are three different versions of the ABS control module.

The ABS control module does not support software downloading. The control modules are supplied with the correct software installed.

Fig 1: Control Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

ABS control module

The control module contains two different micro-processors which receive signals from different sensors in the system. The micro-processors operate in parallel and use a program to compute the necessary ABS and electronic brake force distribution functions. The ABS control module has eight valve coils for the hydraulic valves, four outlet valves and four inlet valves.

The control module has two connectors, one for the car wiring and one for the hydraulic pump.

Fig 2: ABS Control Module With TRACS

Courtesy of VOLVO CARS OF NORTH AMERICA.

ABS control module with TRACS (traction control system) / STC (stability and traction control)

The control module for ABS with TRACS/STC also contains two micro-processors and the four outlet valves and four inlet valves used in the standard ABS control module. The difference (software aside) is that the control module has two extra valves. One valve (Separation Valve-SV) separates the master cylinder from the brake circuit. The other valve (Hydraulic Shuttle Valve-HSV) opens the connection to the brake fluid reservoir during traction control.

Fig 3: ABS Control Module With DSTC

Courtesy of VOLVO CARS OF NORTH AMERICA.

ABS control module with DSTC (dynamic stability and traction control)

The ABS control module with DSTC has twelve valve coils for the hydraulic valves, of which four are outlet valve coils, four are inlet valve coils, two are used for traction control and two more are for DSTC. When replacing the ABS control module in a car with DSTC, the control module must be calibrated according to the instructions for VIDA vehicle communication or manually via a test drive.

Configuring the control module

From model year 2000 the ABS control module with DSTC is factory programmed with software for several models. The central electronic module (CEM) provides information about the car configuration on the Controller area network (CAN) in the car. The ABS control module for DSTC reads the information and uses it for configuration during the first ignition cycle.

Fig 4: ABS Hydraulic Modulator

Courtesy of VOLVO CARS OF NORTH AMERICA.

ABS hydraulic modulator

The ABS hydraulic modulator is located in the engine compartment.

The ABS hydraulic modulator consists of a pump motor and the hydraulic valves which control the pressure to the different hydraulic brake circuits. During ABS control these valves limit the brake pressure to each wheel individually to prevent the wheels from locking. If necessary the valves operate with the hydraulic pump. During stability and traction control the pump and valves combine to supply brake pressure.

There are diagnostics for the pump motor.

NOTE:

The illustration shows the hydraulic modulator for ABS and ABS with TRACS/STC. The hydraulic modulator for ABS with DSTC looks slightly different. The pump motor connector is integrated in the ABS hydraulic modulator.