DSC unit

The DSC unit consists of:

DSC control unit
DSC hydraulic control unit

The DSC hydraulic control unit consists of:

Valve block (piston pump with 2 pistons, solenoid valves, brake pressure sensor)
Pump motor

NOTE: The coils for the solenoid valves are integrated within the control unit. The mechanical components (valve seat, pushrods, etc.) are pressed into the valve block.

Fig 1: Identifying DSC Control Unit And Valve Block

Courtesy of BMW OF NORTH AMERICA, INC.

Item	Explanation
1	DSC control unit
2	Valve block
3	DSC hydraulic control unit
4	Pump motor
5	47-pin plug connection

In every brake circuit, there are pairs of solenoid valves. One intake valve (de-energised open) and one discharge valve (de-energised closed). By activating these correspondingly, the brake pressure at the front wheels and rear wheels is modulated. Changeover of the suction connections of the pump from the low pressure accumulators to the tandem brake master cylinder is performed via the electrical changeover valves.

This brake pressure sensor registers the braking pressure applied via the brake pedal and the brake servo. The brake pressure sensor has a measuring range from 0 to 250 bar. Its zero point is synchronized during driving (no adjustment diagnosis).

The DSC control unit is supplied three times with terminal 30 (pump motor, solenoid valves, control unit electronics). In the voltage supply, there are interdependencies with the automatic engine start-stop function. Observe the diagnosis wiring diagram!