BMW 7 Series: System Components

Control Unit

The Car Access System is located above the steering column on the right-hand side.

For the Comfort Access function, the Car Access System controls the transmitting antennas for the vehicle

The outside door handle electronics are read by the Car Access System.

Fig. 6: Installation Location Of Car Access System 4 With Comfort Access

COMPONENTS DESCRIPTION CHART

1. Car Access System 4 with Comfort Access
2. Junction box electronics
3. Remote control receiver in the diversity module
4. Footwell module
5. Central gateway module
6. Outside door handle electronics
7. Antennas for Comfort Access
8. Central locking components in the trunk

Control Elements

ID Transmitter

The ID transmitter for Comfort Access must be actuated by means of a radio signal. The ID transmitter is therefore equipped with a receiver for the coded 125 kHz radio signal that is transmitted by the Comfort Access antennas. The radio signal wakes the ID transmitter. The ID transmitter registers with the vehicle automatically (authentication).

For this purpose, the ID transmitter emits a coded 315 MHz high-frequency signal to enable identification of the ID transmitter as being valid and belonging to the vehicle.

The ID transmitter is exclusively responsible for use of the Comfort Access system. The ID transmitter has a battery, the service life of the battery in the ID transmitter is about 4 years.

Voltage Monitoring

The ID transmitter monitors its own battery voltage. The battery voltage is monitored in 2 stages.

The first stage signals to the Car Access System 4 that the battery is flat. In response, the Car Access System 4 generates a check control message. The check control message informs the customer that the battery needs to be changed.

If the battery is not changed, the voltage monitoring facility switches to the second stage. This means that the data in the ID transmitter is saved. The ID transmitter is then set to "inoperative".

Fig. 7: Identifying F01/F02 ID Transmitter

COMPONENTS DESCRIPTION CHART

1. Top view of ID transmitter
2. Vehicle unlock button
3. Vehicle lock button
4. Trunk unlock button
5. Follow-me-home lights button
6. Rear view of ID transmitter
7. Transponder coil
8. Battery compartment
9. Mechanical key button
10. Mechanical key

Data for Conditioned Based Service

From terminal status "terminal 15 ON", data for the Conditioned Based Service is transferred to the ID transmitter in the high-frequency range. The ID transmitter then confirms that the transmission was received.

Antennas for Comfort Access

Eight antennas are installed for the Comfort Access system. Five antennas are for the vehicle interior and three are for the vehicle exterior.

The antennas for the exterior and interior are inductive antennas and have a ferrite core.

The antenna transmission frequency is 125 kHz. All messages that are sent via the antennas are encrypted.

Antenna Installation Locations

Exterior antennas

The exterior antennas are installed in the following locations on the F01/F02:

• Door sill on the driver's side, in the center of the vehicle
• Door sill on the front-passenger side, in the center of the vehicle
• Rear bumper in the center

Fig. 8: Identifying Passenger-Compartment Antenna In Door Sills In F01/F02

The antennas are designed to give about 5 feet (1.5 m) of coverage around the vehicle.

The exterior antennas are equipped with a splash-proof plug connection.

Interior antennas

The interior antennas are installed in the following locations in the F01/F02:

• Passenger compartment, front center console
• Passenger compartment, middle center console
• Luggage compartment, left and right
• Parcel shelf

The antenna characteristic is spherical. The entire vehicle interior is covered by the front and middle antennas.

Fig. 9: Identifying Front Passenger-Compartment Antenna In F01/F02

Luggage compartment antenna

The luggage-compartment antennas are of the same design as the interior antennas. They are integrated in the left- and right-hand sides of the luggage compartment.

The luggage-compartment antennas are configured so that they cover the entire luggage compartment.

Outside Door Handle Electronics Module

The outside door handle electronics are connected to terminal 30F and work within a voltage range of 9 V to 16 V. The Car Access System is directly connected to the data line of the outside door handle electronics. This provides the Car Access System with information about the capacitive sensors and the piezo sensors. The status of the "pull" Hall sensor is monitored directly by the Car Access System.

The outside door handle electronics detect the status of the outside door handle using the sensors.

Each change in the status of the outside door handle module triggers the corresponding function.

These functions are:

• Trigger pulse by inserting a hand into the handle recess of the outside door handle; Capacitive sensor 1
• Unlock request by pulling the outside door handle; Hall sensor
• Lock request by pressing the sensitive area on the outside door handle; capacitive sensor 2 plus piezo sensor.

Capacitive sensor 1

If a hand is placed into the handle recess of the outside door handle, for example, this is detected by the outside door handle electronics. On detecting this, the outside door handle electronics send the request to the Car Access System. The request initially contains the information to wake up the Car Access System. The Car Access System is woken and reads the request. Then, the Car Access System establishes communication with the ID transmitter.

The Car Access System switches the remote control receiver on permanently and therefore ensures that the data sent by the ID transmitter can be received.

NOTE: The remote control receiver is integrated in the diversity module.

Capacitive sensor 2/piezo sensor

Touching the sensitive surface generates the capacitive sensor 2 signal. Together with the piezo sensor, a press on the sensitive surface is detected. A lock signal is only triggered if the capacitive sensor and piezo sensor are both actuated.

The outside door handle electronics analyze the two sensors and send the request to the Car Access System.

Outside door handle Hall sensor

The Hall sensor is redundant to the capacitive sensor 1. The Hall sensor is analyzed directly by the Car Access System. The Car Access System monitors the Hall sensor using a clocked voltage supply.

If the vehicle has already been woken by someone reaching into the handle recess, pulling on the outside door handle triggers the unlocking on the vehicle.

In unfavorable situations, it may be necessary to pull on the outside door handle twice to trigger the vehicle unlocking. This is caused if the signal from the capacitive sensor 1 is not present or is implausible.

Door Locks

The vehicle has rapid opening locks in the doors as standard. A spring exerts pretension on the central locking drive for the unlocking procedure. The door is already unlocked before an attempt is made to open it with the outside door handle.

NOTE: However, if the outside door handle is pulled very fast, the vehicle door may not yet be unlocked. In this case, it is necessary to pull the outside door handle a second time in order to open the door.

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