Parking brake application
The driver can activate the EMF parking brake function by pulling on the parking brake button. Thus the way in which the parking brake button is operated emulates the action of a handbrake lever.
The signal from the parking brake button is read by the EMF control unit and transmitted to the DSC control unit as a bus signal. The DSC control unit then decides whether to use the DSC hydraulic modulator or the EMF actuator unit to implement the parking brake function. If the engine is running, the vehicle is held stationary by using the DSC hydraulic modulator; otherwise the EMF actuator unit is used.
The parking brake function is possible at any logical terminal status, i. e. at
- Terminal 0
- Terminal R
- Terminal 15 (and Terminal 50)
Parking brake application at Terminal 0 is specifically made possible by the fact that the EMF control unit is supplied by Terminal 30 and the parking brake button is connected directly to the EMF control unit. If the driver operates the parking brake button at Terminal 0, the EMF control unit is woken up. The EMF control unit in turn wakes up the other control units on the vehicle. Only then can the EMF control unit receive the important signals relating to vehicle standstill. In addition, the changed status of the parking brake can be displayed after the system has been woken up.
The status "parking brake on" is indicated by a red LED on the parking brake button and an indicator lamp on the instrument cluster.
The driver does not have to operate any other controls to apply the parking brake.
Once the parking brake is on, pulling the parking brake button again has no effect.
Scheme 21
| Index | Explanation |
|---|---|
| 1 | Function indicator lamp on parking brake button |
| 2 | Indicator lamp on instrument cluster |
INDEX REFERENCE CHART