Vehicle Dynamics Domain Master (VDDM) (4/163) [2019-2022]: Description

The Vehicle Dynamics Domain Master (VDDM) controls a number of functions, such as:

• Anti-lock Braking System ABS.
• Electrical Brake force Distribution EBD.
• Electronic Stability Control ESC.
• Emergency Brake Assistance EBA.
• Routing information to and from requested destinations.

The Vehicle Dynamics Domain Master (VDDM) is mounted on the hydraulic unit in the engine compartment behind the battery toward the cowl panel.

The control module contains two different microprocessors that receive signals from the different sensors in the system. The microprocessors work in parallel following a program that calculates how the various functions are regulated.

The hydraulic unit of the Vehicle Dynamics Domain Master (VDDM) consists of:

• A pump motor.
• Hydraulic valves.
• Check valves.
• An integrated brake pressure sensor.

The Vehicle Dynamics Domain Master (VDDM) contains 12 electrically controlled hydraulic valves for the brake system. Four of these valves are for outlet, four are for intake and four are for stability and traction control. Some valves that are used when pressurizing the brake system are regulated via analog control, enabling the valves to be controlled linearly. The control module contains an internal pressure sensor that measures brake pressure in the brake system.

The direction-sensitive wheel sensors is located on the left and right rear wheel spindle, the front left and right wheel spindle has non-directional wheel sensors. Using the wheel sensors signal together with the longitudinal acceleration signal from the SRS, the Vehicle Dynamics Domain Master (VDDM) can calculate the wheel speed and direction.

The Vehicle Dynamics Domain Master (VDDM) assists the driver in braking situations using the following functions:

• The brake system pressurization function by filling the brake system with brake fluid, which minimizes the distance between the brake disc and brake pad.
• The hydraulic pump activation function helps the brake system increase brake pressure by activating the hydraulic pump when the vacuum pressure from the brake servo is insufficient.

Other control modules can send requests to the Vehicle Dynamics Domain Master (VDDM) to activate certain brake functions.

The Vehicle Dynamics Domain Master (VDDM) performs start-up tests, at which time the warning lamps that are linked to the functions in the system are activated on the combined instrument display.

Upon replacement of the Vehicle Dynamics Domain Master (VDDM), the system must be calibrated.