Workshop Hints

Emergency Release: The parking brake is manually released directly through the gear drive mechanism.

The tools in the vehicle tool kit to release the parking brake are:

Fig 1: Identifying Emergency Release

Courtesy of BMW OF NORTH AMERICA, INC.

CAUTION: Make sure the transmission is in the Park position before releasing the parking brake!

To release the brake, the extension rod is inserted through a guide tube located in the luggage compartment floor in front of the spare wheel recess (1). Maintain pressure on the tool.

Using the open end wrench and the screwdriver handle, turn the release tool in a counterclockwise direction (2). The cable tension release will be felt during this procedure.

Fig 2: Releasing Tool In Counterclockwise Direction

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: After a power failure/interruption, it is possible that the vehicle can not be moved after releasing the parking brake using the emergency release. The parking lock of the automatic transmission can still be engaged. Refer to the automatic transmission section for the emergency mechanical parking lock release procedure. The parking brake may only be used again if it is released manually after a power interruption. If this is not performed, the parking brake may fail to operate correctly!

Resuming Operation after Emergency Release: When the voltage supply has been restored after the emergency release, the parking brake push button must be pressed 3 times at intervals of approx. 5 seconds to initialize the system . This procedure is also described in the Owner's Handbook and Towing Instructions for BMW 7 Series.

1st press - The control module attempts to release the brake. Since the brake has been released mechanically by the emergency release, the motor cannot run back and blocks. The control module recognizes a disengaged setting.
2nd press - The motor will move forward applying the parking brake. The control module detects an engaged setting. The "P" indicator light illuminates in red.
3rd press - The motor will run backward releasing the parking brake and the "P" indicator light goes out. The parking brake is ready for operation.

Control Module: The parking brake control module (integral in the EMF) is linked to other control modules for communication by the PT-CAN and K-CAN Busses.

Diagnostic communication is provide through the ZGM over the PT-CAN Bus.

Fig 3: Control Module Circuit Diagram

Courtesy of BMW OF NORTH AMERICA, INC.

When the parking brake push button is pressed with the engine running, a fixed brake pressure is built up by the DSC hydraulic unit and applied to the service brakes.

The force applied at the spindle is calculated in the parking brake control module. The control module first determines the current flow of the actuating motor accounting for the temperature of the motor coil (affecting resistance). Hall sensors are mounted on the motor to detect the speed and position. The actuating force is calculated by evaluating the speed reduction of the motor (speed is a function of torque).

Please familiarize yourself with the statements below regarding new procedures when making repairs to the Electro-mechanical Parking Brake. Consult the Repair Information in TIS for additional information on the following procedures:

The parking brake shoes are adjusted the same way as current BMW models by turning the adjuster with a screwdriver through the wheel bolt hole of the wheel hub.

Parking brake cable removal: To remove the parking brake cable assemblies, the EMF top cover must be removed and the end stop plate must be raised with a screwdriver. Using the brake release tool (found in the vehicle tool kit), release the parking brake completely so that the balance arm is turned back to the stop. This will allow the pulleys to rotate far enough so that the cable crimp can be disengaged from the recess in the pulley.

Parking brake initialization: The parking brake must be initialized with the DISplus after replacing the brake shoes. The brake cable "free play" is learned by the EMF control module from the Hall sensors in the actuating motor.

Parking brake lining seating: When the parking brake shoes are replaced, the new brake linings must be seated (bedded down) to achieve adequate holding power. A "Special Bedding Down Routine" is integrated in the parking brake software and can be accessed with the DISplus found under Service Functions - Chassis - Parking Brake - Workshop Braking-in .

The parking brake indicator light in the instrument cluster will flash red (at a low frequency) to signal the standby status of the brake bedding down program. After activating the program, the ignition must not be switched off and the bedding down procedure must be carried out within 30 minutes.

If more than 30 minutes have lapsed, the parking brake button is pushed, or the ignition is turned off before the procedure is carried out, the brake bedding down program will be terminated. The system will resume the normal parking brake function.

The brake linings are seated by the EMF applying a reduced holding force. The braking force at the spindle during this procedure is 20% of the maximum actuating force.

The procedure is activated when the vehicle is stationary (for example: stopped at a traffic light). The brake shoes "scrub" when the vehicle starts off. The EMF releases the parking brakes when a speed of 15 km/h is reached or 30 seconds after the start of the seating procedure.

For safety reasons, the seating procedure is immediately terminated when any DSC function is required. The seating procedure is also terminated when the push button is pressed or the ignition is turned off.

Travel monitoring: Normal parking brake lining wear increases the actuating travel over the service life. Based on the reference point (stop in the EMF unit), the Hall sensors in the actuating motor allows the EMF control module to measure the travel range.

When the defined travel limit is exceeded, information is provided to the driver and a fault is stored in the EMF control module. This can also be checked using the DISplus found under Service Functions - Chassis - Parking Brake - Position Travel Check .

Brake testing on a roller dynamometer: The E65 parking brake operation can be tested on a brake roller dynamometer. The parking brake test can be conducted with the engine running by pressing the parking brake push button. With the engine turned off, the parking brake test can activated by pressing the parking brake push button. The actuating unit will quickly apply and lock the parking brake.

Assembly Mode: Replacement EMFs are shipped in "assembly mode" to suppress activation until the brake cables and EMF are completely assembled and installed in the vehicle. This prevents unintentional operation of the EMF by the parking brake push button and can also be activated (for safety reasons) on an existing EMF in the vehicle when work is being performed.

Before initial operation, the assembly mode must be deactivated by using the DISplus found under: Service Functions - Chassis - Parking Brake - Assembly Mode .

When installing the EMF, make sure that the seal to the body and the seals for the parking brake cables are correctly installed.

Coding data: The coding data for the parking brake system is stored in the EMF control module (EEPROM) and the DSC control module (EEPROM). The coding data is entered by the DISplus when a control module is replaced.