BMW 7 Series: Electromechanical Parking Brake (EMF)

General details

The electromechanical parking brake (EMF) is applied/released by means of the parking brake button on the center console control panel. The parking brake status is indicated by the function indicator lamp on the button and an indicator lamp on the instrument cluster.

Fig. 78: Instrument Cluster Display - Parking Brake ON

The EMF can be applied in all logical terminal statuses (Terminal 0, Terminal R, Terminal 15, Terminal 50).

The conditions for release of the EMF are: Terminal 15 active and brake pedal depressed or automatic transmission parking lock engaged.

Emergency release

The EMF can be released in an emergency by means of a cable. That cable is accessible through the trunk and is under the trunk floor trim. To effect emergency release of the EMF, the red T-shaped handle from the vehicle toolkit is required.

NOTE: Secure vehicle to prevent it rolling before operating the emergency release!

NOTE: After a power supply failure, it may still not be possible to move the vehicle even after releasing the brake with the emergency release facility. The automatic transmission parking lock may still be engaged.

In that case, the parking brake must first be released with the emergency release facility. Then the automatic transmission parking lock must be released using the emergency release facility. The appropriate tool must remain engaged in the parking lock emergency release for that purpose.

NOTE: When the parking brake is to be used again after an emergency release, it can only be done by pushing in the parking brake button. The familiar conditions for releasing the parking brake must also be met.

Installation mode

NOTE: Installation mode sets the EMF actuator unit to the installation position (brake cables extended to maximum). It also prevents the EMF being accidentally applied, e. g. when carrying out repairs.

NOTE: Installation mode can be cancelled either by means of a service function or by driving the car.

Running-in the brakes

While running-in the parking brakes, the EMF applies a defined force to the duo-servo parking brakes.

NOTE: The function for running-in the parking brakes only has t be carried out if:

• the linings of the duo-servo parking brakes have been replaced or
• the rear brake discs have been replaced.

NOTE: The precise procedure for running-in the parking brakes is described in the Repair Instructions under the heading "Adjusting the parking brake". The instructions given there must be followed exactly.

EMF actuating unit

The EMF actuator unit is made up of the following main components:

• EMF control unit
• Electric motor
• Gearbox
• Force sensor.

NOTE: In the event of a fault, the EMF actuator unit can only be replaced as a complete unit.

NOTE: The following are available as separate parts:

• the EMF actuator unit itself
• the bracket for the EMF actuator unit and
• the cables.

NOTE: The EMF control unit detects vehicle standstill on the basis of the following signals:

• Road speed (from ICM)
• Rear axle speed (from DME)
• Wheel-speed signal "DFA_EMF" (from DSC).

Only when those three signals definitively indicate vehicle standstill does the EMF control unit allow operation of the actuator unit.

NOTE: The EMF control unit is connected to the PT-CAN. Integrated in the EMF control unit is a terminal resistor for the PT-CAN.

NOTE: The EMF control unit is connected to the wake-up line.

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 via the wake-up line.

NOTE: On vehicles with the Integrated Active Steering optional extra, the bracket for the EMF actuator unit is bolted to the bracket for the HSR actuator.

On vehicles without Integrated Active Steering, the bracket for the EMF actuator unit is bolted to the rear suspension subframe.

System Circuit Diagram

Electromechanical Parking Brake

Fig. 79: Electromechanical Parking Brake System Circuit Diagram

INDEX REFERENCE CHART

1. Dynamic Stability Control
2. Central Gateway Module
3. Footwell module
4. Car Access System
5. Instrument cluster
6. Parking brake button with function indicator and illumination
7. Fuse for parking brake button (front fuse board, junction box electronics)
8. Fuses for EMF electronics and electric motor (rear fuse board in trunk)
9. EMF control unit
10. EMF force sensor
11. EMF electric motor

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