Electrical - Overview: Other BMW 3 series E46 facelift

Functions Of Roof Function Center

The Roof Function Center (FZD) serves as

Scheme 219

1. Controller of Sunroof Functions
2. Gateway for Rain Light Sensor (Data transmitted from RLS to FZD via LIN Bus then transmitted via K-CAN from FZD to other modules)
3. Evaluator of data from Condensation sensor and calculates relative humidity (data is transmitted via K-CAN to IHKA)
4. Evaluator of data from Interior Electrochromatic Rear View Mirror (data from mirror is converted and transmitted to FRM via K-CAN, FRM dips the outside mirrors)
5. Supplies power to Universal Garage Door opener
6. Activation/Controller of Vanity Mirror lighting, Map/Reading and Interior Light Integration point for Passenger Airbag light, Microphone, and Emergency call button

Scheme 220

The Car Access System 2 (CAS2) serves as

Scheme 221

1. Ignition Switch/Terminal control
2. Master controller for Central Locking, Comfort Access, Power Windows and Sunroof (issues enable command)
3. Actuator/Controller of Electronic Steering Lock
4. "Key" validation device and Electronic Vehicle Immobilization
5. Redundant data storage device for Vehicle Order
6. Storage point for Condition Based Service (CBS) data
7. Control of KL15 and KL 30g relays

Scheme 222

Legend for Car Access System 2

Scheme 223

Legend for Car Access System 2

Central Locking

On the E90, all doors as well as the trunk lid and fuel filler flap are integrated into the Central Locking System.

The central locking can be operated via the following components

1. Remote control/identification transmitter
2. Driver's door lock barrel (door lock)
3. Center-lock button
4. Electronic outer door handle module (TAGE) in connection with comfort access

Scheme 224

Car Access System 2 (CAS2)

As soon as the CAS2 receives the lock/unlock signal from the remote control receiver, it checks whether the identification transmitter is valid and belongs to the vehicle. Only if the check/authentication, which takes a few milliseconds, is successful will the CAS2 forward the request to activate the central locking.

The CAS2, serves as the master control module for the central locking system, as it issues the enable signal to activate a lock/unlock function. An enable status signal is transmitted to the JBE from CAS2 via K-CAN.

Signal Path: Remote control to remote receiver to CAS2; or

Central lock button input to CAS2

Enable signal from CAS2 to JBE via K-CAN (if all doors are closed)

Door status signal from FRM to JBE via K-CAN then JBE via K-Can to CAS2

Example: The request to lock the vehicle, is not executed while the driver's door is open.

Junction Box Electronics Control Module (JBE)

The Junction Box Electronics Control Module is responsible for implementing the lock/unlock operation for the entire vehicle, as it contains the lock/unlock relays which in turn drive the respective lock/unlock motors.

The following central locking relays are activated by JBE

1. Driver's door
2. Rear doors
3. Front passenger's door
4. Fuel filler flap

The central locking function for the trunk lid is activated directly via a power output stage.

Signal Path: Enable signal from CAS2 to JBE via K-CAN; JBE activates lock/unlock function via direct activation of relay(s)

Footwell Module (FRM)

The Footwell Module (FRM) monitors the hall sensors of the door contacts to determine if a door is open or closed. CAS2 indirectly obtains the door status information and uses the information to determine if an enable signal is to be provided to the JBE.

Signal Path: Door contact signals input to FRM; Door status signal from FRM to JBE via K-CAN then forwarded from JBE via K-Can to CAS2.

Unlocking/Locking Vehicle

The central locking system can be activated only when the driver's door is closed.

The vehicle unlocking/locking procedure is initiated by the following system components

1. Remote control/identification transmitter
2. Center-lock button
3. Mechanical key/spare key

Note. The identification transmitter is incorporated with the remote control function and is used solely for Comfort Access. The vehicle activates the identification transmitter by way of a radio signal from the Comfort Access System. This makes it possible to unlock the vehicle without actively using the identification transmitter.

The central locking system activates the following system components

Scheme 225

1. Central locking, driver's and front passenger's door
2. Central locking, rear doors
3. Central locking, fuel tank
4. Central locking, trunk lid Example: If the vehicle is unlocked using identification transmitter/remote control the unlocking procedures is as shown.

Unlocking Procedure

As soon as the unlock button on the identification transmitter is pressed, the signal initially reaches the rear window antenna followed by the remote control receiver. The remote control receiver is located in the diversity module and forwards the signal to the CAS2. The signal from the identification transmitter is verified in the CAS2. If the signal is recognized as valid, the JBE is enabled for the purpose of unlocking the central locking drive units. The JBE now activates the relay to trigger the vehicle unlocking procedure.

Locking Procedure

The vehicle can be locked only after the Footwell Module has evaluated the door contacts and the CAS2 signals that the doors are closed.

Mechanical Key/Spare Key

The footwell module evaluates the Hall sensors for the lock barrel in the driver's door. The CAS2 is informed of the change in status via the K-CAN.

The CAS2 enables the vehicle unlocking/locking procedure. The JBE initiates the vehicle unlocking/ locking procedure.

Locking Button On Vehicle Doors

All four doors can be locked mechanically, by using the separate locking buttons.

If the button on the door is depressed, then the inner door handle of the door to be unlocked must be pulled twice to unlock the vehicle door.

In this situation the Junction Box Electronics Control Module does not activate the central locking.

Opening The Trunk Lid

The trunk lid can be unlocked via the remote control, the identification transmitter, the outer or inner trunk lid release button.

Opening With The Outertrunk Lid Button

As soon as the vehicle is unlocked, the trunk lid can be opened by pressing the outer trunk lid button.

The microswitch switches to ground when the outer trunk lid button is pressed.

The JBE monitors the microswitch. The trunk lid is unlocked and opened when the signal from the microswitch goes to low.

Opening With The Innertrunk Lid Button

As soon as the vehicle is unlocked, the trunk lid can be opened by pressing the inner trunk lid button.

The inner trunk lid button is installed on the A-pillar on the driver's side. It switches to ground. The microswitch is routed directly to the CAS2. As soon as the signal of the microswitch goes to low, the CAS2 sends this status to the JBE. In turn, the JBE activates the motor in the lock of the trunk lid.

Automatic Locking (Personal Profile)

The vehicle is locked automatically when driving at a speed in excess of 16 km/h. The speed signal is made available by the DSC module.

The vehicle is unlocked in connection with Comfort Access (CA) as soon as terminal 15 is switched off.

On vehicles without Comfort Access (CA), the unlocking procedure is triggered by removing the remote control from its holder.

Selective Unlocking

With corresponding coding, the vehicle can also be unlocked selectively. In this case, the driver's door is initially unlocked. The rest of the vehicle is unlocked in response to a renewed unlock request.

Unlocking After An Accident

A locked central locking system is unlocked as soon as the CAS2 receives a crash message from the Multiple Restraint System 5 (MRS5).

On receiving the crash signal, the center-lock button and the remote control receiver are inhibited for the central locking functions. The center-lock button and the remote control receiver are enabled again only after the a change in terminal R OFF/terminal R ON.

Scheme 226

The footwell module is located in the left hand A-pillar. It evaluates the status of the door contacts and reads the Hall sensor signals from the lock barrel in the driver's door and transfers the information via the Junction Box Electronics Control Module to the Car Access System 2.

The Car Access System 2 is installed to the left of the steering column. The CAS2 assumes the master function for the Central Locking System, it has the exclusive system authorization and is simply supported by the other control modules.

The Junction Box Electronics Control Module is integrated in the front power distribution box. The JBE contains the relays for activating the central locking drive modules. The trunk lid is operated via a power output stage. The signals from the outer trunk lid button and center-lock button are also sent to the JBE and transferred to the CAS2.

The remote control receiver is powered by the Junction Box Electronics Control Module.

Controls

Central locking can be operated from the following controls

1. Remote control
2. Identification transmitter
3. Center-lock button
4. Driver's door lock barrel

Remote Control

Each vehicle is delivered with one spare key and two remote control units. The adapter for the spare key is located in the glove compartment.

Note. A third remote control for the vehicle is optionally available. This remote control can be ordered through Spare Parts.

The remote control has three buttons for operating the central locking system.

There is a rechargeable battery in the remote control that is charged by means of a transponder coil in the remote control holder.

The mechanical key is integrated in the remote control.

Scheme 227

Scheme 228

Center-Lock Button

The center-lock button is installed in the instrument panel in the center of the outlet nozzle.

A new feature is that the center-lock button forms one component together with the hazard warning switch, the button for dynamic stability control and the stratification potentiometer.

Scheme 229

Driver's Door Lock Barrel

The lock barrel is connected mechanically via a linkage to the door lock. Hall sensors for the lock barrel are integrated in the door lock.

The footwell module evaluates the signals from the Hall sensors for locking/unlocking purposes.

Central Locking Drive Units

A central locking drive unit consists of an electric drive unit and the unlocking/locking mechanism.

Central Locking Drive Units In Doors

The central locking drive units in the doors are equipped with two motors to facilitate the unlocking/locking and central arrest functions of the vehicle.

Central arrest means that the locking button in the doors is separated mechanically from the central locking drive unit. As a result, the vehicle cannot be opened by pulling the locking button. The Hall sensor for the door contact is additionally integrated in the central locking drive unit.

Central Locking Drive Units For Truck Lid And Fuel Filler Flap

The central locking drive units for the truck lid and fuel filler flap are each equipped with a motor for unlocking/locking purposes.

Manually Release For Fuel Filler Flap

The fuel filler flap can be unlocked manually in the event of an electrical defect. The release device is located in the luggage compartment on the right behind the luggage compartment cover.

1. Remove cover
2. Pull green knob with fuel pump symbol.

Lock Barrel, Trunk Lid

The trunk lid can be unlocked via the lock barrel using the mechanical key or spare key. This a pure mechanical unlocking function and triggers no response in the central locking.

Emergency Trunk Lid Release

The emergency release for the trunk lid is integrated in the luggage compartment. The central locking of the trunk lid is released by pulling the pull handle for the emergency release.

Scheme 230

A detailed description of the truck lid emergency release facility is provided in the E90 Owner's Manual.

Scheme 231

Scheme 232

Comfort Access

Comfort Access (SA 322) is offered as an option for the E90.

"Comfort Access" is a passive access system. This means the vehicle is unlocked by grasping the outer door handle, provided the identification transmitter is located within a radius of no more than approx. .5 - 1.5 m from the vehicle.

With Comfort Access it is sufficient for the driver to simply carry the identification transmitter on his/her person in order to open or start the vehicle. "Keyless" access to the vehicle was implemented for the first time on the E65 and has been adapted for the E90.

As with many of these systems the operation/functions are distributed among several different control modules. Comfort Access utilizes the same modules that are utilized for the Central Locking function plus two more.

Scheme 233

As soon as the CAS2 receives a request signal it must verify if a valid ID Transmitter is located with range of the antenna. CAS2 requires that the antenna in the area of the request transmit a request for validation to the ID Transmitter.

The ID transmitter transmits a signal to the remote control receiver, which in turn forwards the signal to the CAS2 where the signal is checked to be valid and belonging to the vehicle. Only if the check/authentication, which takes a few milliseconds, is successful will the CAS2 forward the request to activate the specific function.

The CAS2, serves as the master control module for the central locking system, as it issues the enable signal to activate a lock/unlock function. An enable status signal is transmitted to the JBE from CAS2 via K-CAN.

The Junction Box Electronics Control Module is responsible for implementing the lock/unlock operation for the entire vehicle, as it contains the lock/unlock relays which in turn drive the respective lock/unlock motors.

The following central locking relays are activated by JBE

1. Driver's door
2. Rear doors
3. Front passenger's door
4. Fuel filler flap

The central locking function for the trunk lid is activated directly via a power output stage.

Signal Path: Enable signal from CAS2 to JBE via K-CAN; JBE activates lock/unlock function via direct activation of relay(s)

The Footwell Module (FRM) monitors the hall sensors of the door contacts to determine if a door is open or closed. CAS2 indirectly obtains the door status information and uses the information to determine if an enable signal is to be provided to the JBE.

Signal Path: Door contact signals input to FRM; Door status signal from FRM to JBE via K-CAN then forwarded from JBE via K-Can to CAS2.

Comfort Access Control Module

The Comfort Access Module controls/activates the antennas located on the exterior and interior of the vehicle, plus reads/transfers the data received from the Electronic Outer Door Handle Module to the CAS2.

Electronic Outer Door Handle Module (TAGE)

The Electronic Outer Door Handle Module (TAGE) transmits door handle status data via CAS BUS(K-BUS) to the Comfort Access module, which in turn forwards the data to CAS2. Information from the door handle that is transmitted is primarily related to changes at the capacitive sensors and hall sensors integrated into the door handle.

Functions Of Comfort Access

The main advantages of Comfort Access (CA) are

Scheme 234

1. Passive Entry - Unlocking the vehicle without actively using the ID transmitter
2. Passive Go - Starting engine without inserting the ID transmitter into its holder
3. Passive Exit - Locking authorization without actively using the ID transmitter

Note. In connection with the comfort access system, the vehicle must activate the identification transmitter by means of a radio signal so that the transmitter is registered with the vehicle (authentication).

Passive Entry

Passive entry enables access to the vehicle without operating the Identification Transmitter/Remote Control.

Note. The vehicle cannot be woken and opened without a valid ID transmitter being present within a .5-1.5 m radius from a specific external antenna.

The vehicle in sleep mode is woken with the presence of a valid ID transmitter/remote control and activation of the Comfort Access System is started by grasping the outer door handle.

Unlocking

The capacitive sensor in the Electronic Outer Door Handle Module (TAGE) recognizes that the handle has been grasped and activates the transmit antenna. The transmit antenna sends a 125 kHz signal to the identification transmitter. In turn, the identification transmitter sends a 315 MHz high frequency signal to the remote control receiver, which contains the authentication request.

The CAS2 checks the authentication of the identification transmitter.

Following successful authentication, the CAS2 issues the enable signal to unlock the vehicle and initiates the vehicle unlocking procedure. The JBE executes the unlocking procedure.

Note. At this point the steering is not yet unlocked.

Opening Trunk Lid

An authentication check also takes place before opening the trunk lid, an identification transmitter must be located within the rear area of the vehicle.

After successful authentication, the trunk lid can be unlocked and opened with the outer trunk lid button.

Passive Go

The passive go function makes it possible to start the vehicle without the ID transmitter being inserted in its holder.

Note. The vehicle cannot be started without a valid ID transmitter being located in the interior of the vehicle.

Issuing Start Enable

After the door has been opened, the CAS2 starts the check after 3 s to establish whether there is a valid ID transmitter in the vehicle. The CAS2 instructs the Comfort Access control module to again send out the identifier for a valid ID transmitter.

The Comfort Access Module sends the request via the interior antennas.

The identification transmitter replies with a code via the high frequency link (315 MHz) to the remote control receiver. This code contains data for the electronic vehicle immobilizer.

The car access system 2 issues the enable to start the engine for the DME/DDE and the electric steering lock is unlocked.

Passive Exit

The passive exit function makes it possible to lock the vehicle without actively using the ID transmitter/remote control.

Note. The vehicle cannot be unlocked without a valid identification transmitter within a .5-1.5 m radius from a specific external antenna.

After the vehicle door has been closed, the locking procedure is started by touching the recognition point/area on the outer door handle. The electronic outer door handle module sends the request to lock the vehicle via the K-Bus to the Comfort Access System.

Based on the exterior and/or interior antennas, the Comfort Access System checks where the ID transmitter is located. The ID transmitter is instructed to send an authentication signal. In turn, the identification sensor sends encrypted data via the high frequency link to the remote control receiver.

The CAS2 checks whether the ID transmitter is valid. Upon successful completion of the check, the CAS2 issues the enable signal to lock the drive units and initiates the steering locking procedure.

The JBE activates the central locking drive units.

Special Comfort Access Functions

The Comfort Access System additionally features special functions that are determined by the actions of the vehicle user such as

ID Transmitters Remain in Vehicle

If an ID transmitter remains in the vehicle interior, by checking via the interior antennas, the car access system 2 recognizes whether there is a valid identification transmitter in the vehicle interior.

If a valid identification transmitter is detected in the vehicle interior and the vehicle is locked by means of another valid identification transmitter, the identification transmitter located in the vehicle interior is set to "invalid".

For the Comfort Access System, this identification transmitter is considered as no longer belonging to the vehicle until the vehicle is unlocked again.

ID Transmitter Remains in Trunk

If an ID transmitter is in luggage compartment, upon closing the trunk lid, it is immediately opened (automatically).

If there is an identification transmitter in the luggage compartment of the locked vehicle with the trunk lid open. An audible and visual signal draws the customer's attention to the fact that the identification transmitter has been left in the luggage compartment.

On request from the CAS2, the Comfort Access control module starts the check via the interior antennas. The valid identification transmitter in the luggage compartment is recognized via the luggage compartment antenna. Consequently, the CAS2 does not issue the enable signal to lock the trunk lid.

The trunk lid cannot be closed before the ID transmitter has been removed and is located outside the luggage compartment.

Note. An ID transmitter can be locked in the truck if a second valid ID transmitter is identified as being on the exterior of the vehicle within the radius of the bumper antenna or if the valet function is active.

Engine Start Disable

The engine cannot be started if the identification transmitter is located in the luggage compartment of the unlocked vehicle.

Note. The CAS2 issues the enable signal for starting the engine only when a valid identification transmitter has been detected in the vehicle interior.

Starting Engine Without ID Transmitter

The function makes it possible to start the vehicle within 10 s after "engine OFF" without detecting the identification transmitter. This function is intended for cases where the identification transmitter is not detected due to high frequency interference, as an example.

Check Control Message, Terminal 15

The Comfort Access System enables terminal selection without the ID transmitter being inserted in its holder. It is possible that terminal 15 is selected by pressing the STARTSTOP button. A corresponding check control message is shown in the instrument cluster after the door is opened. An audible signal also sounds.

Note. The battery may be discharged if the driver ignores the warnings and locks the vehicle.

Unintentional Wake-up Function

The sensors are subject to a check procedure in order to avoid waking the electronic outer door handle module by touching the outer door handle without a valid identification transmitter.

The identification transmitter is requested to send an authentication signal. If no valid ID transmitter is detected, the electronic outer door handle module receives this information from the CAS2. In this case, the electronic outer door handle module remains inactive until a valid identification transmitter is detected.

Locking With Engine Running

The vehicle can also be unlocked with the engine running if the engine was started with passive go. When leaving the vehicle, the ID transmitter must also be taken and the vehicle locked from the outside.

Components Of Comfort Access System

The following graphic shows all components of the Comfort Access System with the respective control modules and control components.

Scheme 235

In addition to providing Central Locking functions, the option SA 322 Comfort Access is installed to facilitate Passive Entry, Passive Go and Passive Exit functions.

The Comfort Access control module is located at the right rear of the luggage compartment.

The Comfort Access Module controls/activates the antennas located on the exterior and interior of the vehicle, plus reads/transfers the data received from the Electronic Outer Door Handle Module to the CAS2.

Scheme 236

Voltage Monitoring

The ID Transmitter monitors its own battery voltage in two stages

1. First stage the ID Transmitter signals to the CAS2 that the battery is "flat" (discharged). In response, the CAS 2 generates a check control message. The check control message informs the customer that the battery needs to be changed.
2. Second Stage if the battery is not changed, the voltage monitoring facility initiates a function which saves the data in the ID Transmitter is saved and then ID Transmitter is set/made "inoperable".

Antennas For Comfort Access

Six antennas are installed for the comfort access system. Three antennas are located in the exterior and three in the interior.

The antennas for the exterior and interior are inductive antennas and have a ferrite core which contributes to their compact size. This is of particular advantage for accommodating the antennas in the outer door handles.

The transmit frequency of the antennas is 125 kHz. All messages that are sent via the antennas are encrypted.

Antenna In Outer Door Handles

The antenna in the outer door handles is an integral part of the electronic outer door handle module. The antenna characteristic is structured such that it covers the area about the vehicle doors.

Antenna In Bumper

The antenna in the rear bumper is of the same design as the interior antennas. It features a waterproof plug connection to ensure no water enters the antenna.

The antenna characteristic is structured such that it covers the rear area and enables access to the luggage compartment.

Antennas For Passenger Compartment

The antenna characteristic is spherical. The entire vehicle interior is covered by the two interior antennas.

The interior antennas are important for checking whether there is an identification transmitter located in the interior.

Antenna For Luggage Compartment

Due to its design, the luggage compartment acts as a "separate" area in the vehicle. This arrangement makes it easier for the comfort access system to identify the identification transmitter in the luggage compartment.

The luggage compartment antenna is of the same design as the interior antenna. The antenna characteristic is laid out such that it covers the entire luggage compartment.

Scheme 237

The outer door handle contains the components of the Electronic Outer Door Handle Module (TAGE), which is connected to terminal 30 and operates within a voltage range from 9 V to 16 V.

Scheme 238

The electronic outer door handle module is connected to the vehicle via the K-Bus thus making available the information from the capacitive sensors and the Hall sensor.

Design

The Electronic Outer Door Handle Module (TAGE) contains the following components

1. 3 sensors Capacitive sensor 1 for unlocking the vehicle Capacitive sensor 2 for locking the vehicle A Hall sensor for pulling the outer door handle
2. Inductive antenna for the exterior
3. Electronic module for outer door handle and interface for CAS-bus.

With the aid of 3 sensors, the TAGE module detects the status of the outer door handle. Each change in the status of the outer door handle module triggers on of the corresponding functions

1. Trigger pulse when a hand is moved around the outer door handle; capacitive sensor 1
2. Unlock request by pulling the outer door handle; Hall sensor
3. Lock request by touching the recognition point/area on the outer door handle; capacitive sensor 2

Sensors

To protect the battery, the TAGE module switches off the capacitive sensors for the driver's side after the vehicle has been at rest for 192 hours. The capacitive sensors on the passenger's side are switched off after 72 hours.

Functional Principle Of The Capacitive Sensor

The capacitive sensor consists of three capacitor plates (electrodes). The dielectric is the air gap between the door handle and the body/door panel of the vehicle. One capacitor plate is the car body including the surrounding vehicle. The other two capacitor plates are located in the outer door handle.

The outer door handle is split in two parts with respect to the capacitor plates. One capacitor plate is in the outer door handle. The other capacitor plate is contained in the grooved area on the upper portion of the outer door handle. The functional principle of the capacitive sensor is based on a change in the electrical field between the capacitor plates, which results in a change in the capacitance of the capacitor. A change in capacitance occurs (increase) whenever a hand is placed between the body and the outer door handle (grabbing of the handle). The electronic circuitry in the outer door handle wakes up based on a defined change in capacitance, which is referred to as triggering.

The capacitive sensor responds with a pulse only to fast changes in its capacitance. Changes in its environment such as slow soiling of the outer door handle or rain therefore have no influence on the function of the capacitive sensor.

When unlocking/locking the vehicle, the sensors are mutually blocked for a period of 2 sec., meaning that after locking, unlocking is inhibited for 2 sec and vice versa.

Capacitive Sensor 1

Capacitive Sensor 1 is responsible for initiating the Unlock request by generating pulse when a hand is held between the "capacitor plates", door handle and door panel/body. The pulse wakes up the electronic circuitry in the TAGE. If the vehicle is in sleep mode, the TAGE will send a wake up request via K-Bus to the Comfort Access Module and CAS2. CAS2 will request that a signal be sent from the external antenna to the ID Transmitter asking for a validation signal. The Comfort Access module switches on the remote control receiver in order to receive the validation signal sent from the ID transmitter.

Scheme 239

Capacitive Sensor 2

A change in capacitance at sensor 2 is achieved by placing the thumb on the grooved area of the door handle. The change in capacitance generates a signal from sensor 2, resulting in the TAGE sending a lock request via the K-Bus (CAS-Bus) to the CAS2.

Hall Sensor Of The Outer Door Handle

The Hall sensor is redundant to the capacitive sensor 1. If the TAGE has switched off the capacitive sensors, the Hall sensor is still operational after 192 hours which allows the unlocking procedure to also be started via the Hall sensor.

The Hall sensor changes its status from low to high when the outer door handle is pulled. The TAGE monitors the status of the hall sensor and consequently detects whether access to the vehicle is requested.

The monitoring cycle takes place every 40 ms in order to save the vehicle battery. A signal is triggered when the sensor reaches a defined threshold. The electronic outer door handle module detects the signal and switches on the power supply of the Hall sensor for checking purposes.

Lock In Driver's Door & Front Passenger's Door

The capacitive sensor 1 initiates the vehicle unlocking procedure.

The lock in the driver's door and front passenger's door is equipped with an additional spring to ensure the vehicle can be opened fast enough. The spring exerts pretension on the central locking drive unit for the unlocking procedure. The door is already unlocked before an attempt is made to open it with the outer door handle.

Note. If pulled very fast, however, it may be necessary to pull the outer door handle a second time in order to open the door.

Scheme 240

Legend for Comfort Access

Scheme 241

Interior Lighting

The components installed with the interior lighting system for the E90 are

1. Interior Light with Interior Light Switch
2. Interior Light with Interior Light Switch
3. Reading Light with Reading Light Button, Driver and Passenger
4. Top Light, Driver and Passenger
5. Interior Light
6. Interior Light with Interior Light Switch
7. Reading Light with Reading Light Button, Driver and Passenger
8. Top Light, Driver and Passenger
9. Luggage Compartment Light
10. Vanity Mirror Light, Driver and Passenger
11. Footwell Lights, Driver and Passenger
12. Courtesy Light, Driver and Passenger

Control Modules For Interior Lighting

The "interior lighting" function is distributed over several control module that communicate with each other via the K-CAN.

1. Footwell Module (FRM) is responsible for switching the interior lighting on & off.
2. Roof Functions Center (FZD) is responsible for the interior lighting components in the roof area.
3. Junction Box Electronics Control Module (JBE) is the interface to the luggage & glove compartment lighting.
4. Car Access System 2 (CAS2) receives the unlock signal and sends the instructions through the footwell module to switch on the interior lighting.

The interaction of these three control units is described in more detail on the following pages.

All interior lighting outputs of the Footwell Module are pulse-modulated to ensure that the interior lighting functions are at a constant brightness level in the event of voltage fluctuations. The pulse width modulation is also used for the soft ON/OFF function.

The Footwell Module features the following functions for the interior lighting

1. Switching the interior lighting on/off
2. Electric load shut-down after 16 minutes
3. Instrument lighting, terminal 58g

Switching On Interior Lighting

The footwell module receives numerous input signals that switch on the interior lighting. For instance, the input signals from the footwell module are read in directly or received via the K-CAN.

The input signals for the interior lighting are listed in the following.

INPUT SIGNAL INDEX

Switching-On Conditions

The interior lighting is switched on in response to one of the following conditions

1. Unlock via barrel lock in driver's door
2. Unlock via remote control/identification transmitter
3. Terminal R OFF when terminal 58g was ON
4. Receiving crash signal
5. Lock button on remote control/ ID transmitter pressed when the central locking has been in central arrest state for longer than 10 s
6. Interior lighting button pressed.

Switching Off Interior Lighting

The FRM receives numerous signals to switch off the interior lighting via the K-CAN or are obtained indirectly by the FRM.

Switch-Off Conditions

The interior lighting is switched off under the following conditions

1. Central locking in central arrest, all doors and the trunk lid are closed
2. Terminal R OFF after 16 mins
3. Interior lighting button pressed for longer than 3 s
4. Terminal R ON with doors closed
5. Terminal 58 ON and terminal R OFF.

The interior lighting is switched off if no door is opened within 20 s.

1. The interior lighting is switched off if the vehicle is unlocked via the remote control/identification transmitter and no door is opened after 20 s.
2. Terminal R OFF and a vehicle door is opened for longer than 1 min
3. "Power down" via diagnosis

Electric Load Shutdown

By way of terminal R OFF, the interior lighting system is switched off by the FRM after 16 min. For this purpose, the Footwell Module sends the electric load shut-down information via the K-CAN.

The Roof Functions Center (FZD) receives this information and switches off the interior lighting in the roof area.

The interior lights that are switched on directly by the FRM are also switched off.

Terminal 58g

The FRM makes available terminal 58g via the K-CAN. Terminal 58g is pulse width modulated and features the following two brightness levels

Scheme 242

1. The brightness level for the locator lighting can be set individually via the rocker switch on the column stalk.
2. The brightness level for the function lighting is not dimmed and is switched on at full brightness.

Roof Functions Center (FZD)

For the interior lighting system, the Roof Functions Center represents the interface to the Footwell Module since both control modules are connected to the K-CAN. For instance, the FZD can receive instructions to switch the interior lighting on or off via the K-CAN from the FRM. The FZD is the link to the rear interior lighting unit.

The interior lighting functions in the Roof Functions Center are

1. Switching the interior lighting on/off on request from the Footwell Module
2. Reading the signals from the interior light buttons and transferring them to the Footwell Module

The Roof Functions Center receives the terminal 58g signal from the Footwell Module via the K-CAN and activates the lighting in the buttons.

The JBE is responsible for switching the luggage compartment and glove compartment lighting on and off by providing the ground connection for the lighting system.

Luggage Compartment Lighting

The status of the trunk lid contact changes when the trunk lid is opened manually or via the remote control/ID Transmitter, which causes the signal to go to a low level. The JBE evaluates this signal and switches on the luggage compartment lighting.

The status of the trunk lid contact switch changes when the trunk lid is closed again, this causes the signal to go to a high level and the JBE switches off the luggage compartment lighting.

The JBE also switches on the luggage compartment lighting when the trunk lid is opened from the inside by pressing the button on the A-pillar.

Glove Compartment Lighting

Opening the glove compartment operates a microswitch that switches on the glove compartment lighting.

The CAS2, serves as the master control module for the Central Locking System and issues the enable signal to activate/deactivate central locking which in turn transmits a signal, via K-CAN, to the FRM requesting the illumination of the interior light.

As soon as the CAS2 receives a request to unlock/lock, the signal is checked whether it is valid and belongs to the vehicle. Only if the check is successful will the CAS2 forward the request to lock/unlock via JBE plus activate interior lighting via the FRM.

Interior Lighting Components

The "interior lighting" function is distributed over several control units that communicate with each other via the K-CAN. .

Scheme 243

Interior Lighting Unit, Front

The front interior lighting unit consists of

Scheme 244

1. Reading lamp, driver's side with button
2. Interior light with button
3. Reading lamp, front passenger's side with button
4. Top light.
5. Emergency call button
6. Passenger airbag OFF lamp
7. Microphone
8. Slide/tilt sunroof
9. Color of roof area

Interior Lighting Unit, Rear

The rear interior lighting unit consists of

Scheme 245

1. Reading lamp, rear left/right with button
2. Interior light with button
3. Top light
4. Cover for ultrasonic interior protection (movement detector) on vehicles with DWA.

Scheme 246

Scheme 247

Power Windows

The Power Window functions available in the E90 are

1. Opening and closing
2. Opening and closing with toll function
3. Convenient opening and closing
4. Indirect anti-trapping protection
5. Panic mode
6. Load shut-down at terminal 50
7. Thermal protection of power window motors

Scheme 248

The car access system 2 is the master control module for opening and closing the windows.

The relays for the power window motors for the driver's and passenger's side are installed in the Footwell Module.

The relays for the power window motors of the rear left/right doors are installed in the Junction Box Electronics Control Module.

Opening And Closing Car Access System 2

The Car Access System 2 is the central control function for electric opening and closing of the power windows. This means that the CAS2 issues the signal to enable the open and close function for the power windows. The FRM and the JBE activate the power window motors.

The FRM and the JBE monitor the motor speed of the respective power window motors. In this arrangement, the FRM or JBE can respond to overheating or possible blocking of the power window motors in the event of an object being trapped in the windows.

Opening And Closing

The corresponding power window motor is activated in OPEN or CLOSE direction by pressing or pulling the power window switches to the first notch position. The power window motor is driven until the corresponding power window switch is released.

To ensure the power window is closed reliably, the power window motor is briefly driven to block status at the upper stop.

Opening And Closing With Toll Function

The toll function is implemented for all power windows (window regulators). The corresponding power window motor is driven in OPEN or CLOSE direction by pressing or pulling a power window switch beyond the limit stop. The power window motor moves the window automatically until it is completely open or closed. Power window operation is stopped when the power window switch is pressed or pulled again.

Examples: The following examples illustrate the interaction of the individual components for the power windows function.

Switch Cluster, Driver's Door

1. The signal is routed via the LIN-bus to the footwell module when the power window switch for the window in the driver's door or front passenger's door is operated. The footwell module drives the corresponding power window motor.
2. The signal is routed from the driver's door switch cluster via the LIN-bus to the footwell module when the power window switches for the windows in the rear doors are operated. The FRM sends the signal via the K-CAN to the JBE.

On receiving the signal, the Junction Box Electronics Control Module activates the corresponding power window motor.

Power Window Switch, Front Passenger's Door

The signal is routed to the JBE when the power window switch in the front passenger's door is operated. The JBE sends the signal via the K-CAN to the footwell module. The FRM drives the power window motor.

Power Window Switch, Rear Doors

The signal is routed to the JBE when the power window switches in the rear doors are operated. The JBE drives the power window motor.

By way of example, the opening and closing procedure for one of the rear windows is illustrated in the signal progression in the following graphic. The opening or closing function is initiated from the driver's door switch cluster.

Scheme 249

Convenient Opening And Closing

Convenient opening or closing can be performed with the remote control/ID transmitter via the door lock in the driver's door or the outer driver's/passenger's door handle.

Convenient Opening With Remote Control

The convenient opening function is initiated by unlocking the vehicle with the remote control and keeping the button pressed for longer than 5 s.

Initially, the front windows are opened, followed after a short time delay by the rear windows and the slide/tilt sunroof. If the fold in/out outside mirrors are optionally installed and the mirrors are folded in, the mirrors will be folded out at the same time the rear windows are opened.

The signal from the remote control is made available to the CAS2 via the remote control receiver.

The CAS2 issues the enable to operate the power windows and initiates the convenient opening function. The footwell module and the Junction Box Electronics Control Module correspondingly activate the power window motors.

Convenient Closing With Remote Control

The convenient closing function is initiated after locking the vehicle with the remote control and keeping the button pressed for longer than 5 s. Initially, the slide/tilt sunroof is closed followed with a short time delay by the rear/front windows.

If the folding outside mirrors option is installed, the mirrors are folded in simultaneously as the rear windows are closed.

Convenient Opening And Closing Via Driver's Door Lock Barrel

There are two Hall sensors installed in the door lock for the purpose of opening and closing the vehicle. The Hall sensors enable the FRM to detect the position of the mechanical key or of the spare key in the lock barrel.

The key must be turned to the open or close position to initiate the convenient opening and closing function. The convenient opening or closing function is initiated when the key is held in this position.

The FRM sends the request via the K-CAN. On conclusion of the corresponding check, the CAS2 initiates the convenient opening or closing procedure.

Convenient Closing With Comfort Access

In connection with Comfort Access, the convenient closing function is triggered via the driver's/passenger's outer door handle.

It is sufficient to touch the sensitive area of the outer door handle in order to trigger the convenient closing function via the door handle. Convenient closing starts if the sensitive area is touched for longer than 5 seconds. The identification transmitter must be within an approx. 2 m radius of the vehicle.

Note. Touching the outer door handle corresponds to pressing the lock button on the ID transmitter.

Indirect Anti-Trapping Protection

Essentially, the indirect anti-trapping function does not prevent an object being trapped but rather it limits the trapping force to maximum 80 N. The power window motor is reversed on exceeding this trapping force.

The footwell module and the Junction Box Electronics Control Module monitor the activated power window motors. The indirect anti-trapping function of the front windows is activated by the footwell module. The indirect anti-trapping function of the rear windows is activated by the Junction Box Electronics Control Module.

The indirect anti-trapping function in the E90 is based on the evaluation of the hall pulses from the power window motors. The speed is derived from the Hall pulses of the power window motors. Speed fluctuations within certain ranges trigger the indirect anti-trapping function so that the windows are opened. Operation of the power window switches if ineffective while the windows are opened.

The window can only be operated in jolts if no operable anti-trapping function is detected as the result of defective Hall sensors. The power window (window regulator) is in emergency mode and must be reinitialized.

Panic Mode

Panic mode is triggered by overpulling - releasing - overpulling (overpulling = pulling beyond limit stop) the power window switches. It is necessary to release and overpull the switch again in order to deactivate the anti-trapping protection function, which is still active the first time the switch is overpulled.

Overpulling the power window switch the second time within 4 s closes the window with maximum force.

Note. The indirect anti-trapping function is no longer active in this case. The window closes at the maximum closing force and does not reverse.

Load Shut-Down, Terminal 50

To protect the battery, operation of the power windows is interrupted during the vehicle start procedure.

The CAS2 revokes the enable for power window operation, in order to interrupt current operation of the power windows.

The signal is received by the FRM and JBE via the K-CAN. The power window switches must be pressed again following an interruption in operation. The corresponding function is not executed if the power windows are operated during the start procedure.

The enable for operation of the power windows is not issued until the start procedure has been completed.

Thermal Protection Of Power Window Motors

The FRM and the JBE monitor the power window motor temperature. The motor temperature is determined based on the outside temperature, motor running time and the time the motor is stationary (not operative).

Each motor can be switched off individually to prevent the power window motors overheating during operation of the power windows (window regulators). The motor is then deactivated for a defined period of time.

The thermal protection function does not prevent the windows from being opened in the case of trapping. Once started, a power window function is not interrupted by the thermal protection facility.

In panic mode the window can still be closed even when the thermal protection function is active.

Driver's Door Switch Cluster

The driver's door switch cluster is connected via the LIN-bus to the footwell module. The power window switches are resistance-coded and switched to ground.

Scheme 250

Signal Evaluation Of The Power Window Switches

The signals of the power window switch in the driver's door are evaluated directly by the driver's door switch cluster and transferred to the footwell module via the LIN-bus.

The signals from the power window switches in the front passenger's door as well as the power window switches of the both rear doors are evaluated by the JBE.

Signal evaluation of the power switches is summarized in the following table.

POWER WINDOW SWITCHES SIGNAL EVALUATION

The remote control or the ID transmitter can initiate the comfort opening/closing procedure for the power windows. The operating procedure is defined in the Owner's Handbook.

Power Window Motors

The power window motors are equipped with Hall sensors that generate signals during motor operation, for the purpose of monitoring motor operation, and are evaluated by the FRM and JBE for the anti-trapping function.

Initialization Of Power Windows

The front and rear power windows can be initialized via the power window switches or the BMW diagnosis system.

Note. The power windows can only be moved in small increments if not initialized.

Initialization Via Power Window Switches

The following procedure must be performed to initialize the system

1. Completely close window by pulling the power window switch beyond the limit stop.
2. Briefly interrupt pulling/release the power window switch and then pull the switch upwards again for approx. 1 s.

Slide/Tilt Sunroof

The roof functions center receives signals from the other control units for the functions of the slide/tilt sunroof. The executing control unit is the roof functions center. On request, it drives the sunroof motor and simultaneously monitors the motor rotation.

The following sunroof functions are integrated in the FZD

1. Reading operating requests
2. Controlling sunroof motor Anti-trapping protection Blocking protection Thermal protection
3. Panic mode
4. Load cut-out during start procedure
5. Terminal 58g
6. Initialization

Scheme 251

The Car Access System 2 is the master control module for and issues the enable command for opening and closing the sunroof.

The Footwell Module supplies input signals for the convenient opening/closing function and monitors the door contacts.

Roof Function Center (FZD)

The Roof Functions Center (FZD) controls and monitors the slide/tilt sunroof motor, plus it contains the relays to drive the sunroof motor.

Comfort Access (CA)

Comfort Access module (if installed) supplies input signals for the convenient opening/closing function.

Slide/Tilt Sunroof Button

The button for the slide/tilt sunroof is located in the roof functions center. When operated, the button sends a low signal to the electronic module that drives the sunroof motor corresponding to the button selection.

Remote Control/ID Transmitter

The convenient opening/closing function is initiated by pressing the button on the remote control/identification transmitter.

The convenient opening/closing function is triggered by turning and holding the mechanical key or the spare key in the open/ close position in the driver's door lock barrel.

Outer Door Handle

The convenient closing function can be triggered by touching the sensitive area of the outer door handle.

Slide/Tilt Sunroof Motor

The FZD activates the integrated relays when it receives the request for the slide/tilt sunroof. The sunroof motor receives its voltage supply via the relays. The FZD monitors the relay contacts to ensure trouble-free control of the motor and therefore of the slide/tilt sunroof. In addition, the motor speed is calculated from the pulses of the Hall sensors and the direction of rotation of the corresponding motor.

The distance the slide/tilt sunroof must cover during the opening or closing procedure is defined in the FZD. The sunroof motor generates a certain number of pulses within this range and therefore recognizes the end positions of the slide/tilt sunroof.

Anti-Trapping Protection

The indirect anti-trapping function is determined on the basis of the power intake of the sunroof motor. The anti-trapping function is triggered if the closing force increases by 80 to 90 N and the sunroof is moved back by approx. 200 mm.

Blocking Protection

The FZD detects blocking if the pulses from the Hall sensor fail for more than 500 ms during the opening or closing procedure, which results in the power supply to the motor being switched off.

Thermal Protection

The thermal protection of the slide/tilt sunroof motor is calculated in the FZD. For this purpose there is a temperature sensor on the pc-board of the FZD which determines the ambient temperature.

The FZD calculates the current motor temperature based on the operating time of the sunroof motor. The warm-up and cool-down phases are stored based on a temperature model in the FZD. The current temperature is entered in the memory before the FZD assumes sleep mode. When the vehicle is restarted, the motor temperature is adjusted to the ambient temperature.

The slide/tilt sunroof is closed at maximum closing force in panic mode. Panic mode can be activated up to a vehicle speed of 16 km/h. Panic mode is triggered by pressing, releasing, again pressing and holding the sunroof button.

The anti-trapping function is not active.

When the exterior lights are switched on, the FRM sends this information via the K-CAN. The FZD receives this information and adopts the set value for the instrument lighting.

The LED in the button for the slide/tilt sunroof is activated, pulse width-modulated by the FZD. This achieves a constant brightness of the LED even under fluctuating system voltage conditions.

Button For Slide/Tilt Sunroof

The button is located in the FZD and has 3 operating directions. (Open/Close/Tip-up)

The motor of the slide/tilt sunroof features 2 Hall sensors. The Hall sensors are located on the motor shaft and are offset by 90 degrees with respect to each other.

When the motor is running, this results in two offset Hall signals that are used to register the direction of rotation of the motor and for the anti-trapping protection function.

Initialization

Initialization of the slide/tilt sunroof involves the following procedures that are necessary to ensure complete operation of the slide/tilt sunroof

1. Normalizing The normalizing procedure involves finding the mechanical end position at the limit stop of the "tilt" position. This position is stored and is used to calculate the remaining end positions of the slide/tilt sunroof.
2. Learning the characteristic The learning procedure registers the closing force necessary for each direction of the slide/tilt sunroof and stores this value.

Complete functionality of the slide/tilt sunroof can be guaranteed only by full initialization. The initialization procedure can be initiated with the button for the slide/tilt sunroof or via the diagnosis system.

Procedure

Note. The control button must remain pressed during the entire initialization procedure. The initialization procedure must be repeated if the button is released.

Initialization is performed as follows

1. Press and hold sunroof button in sunroof "tilt" direction
2. After approx. 15 s, the initialization run starts in the "tilt" direction and stores the end position
3. The slide/tilt sunroof is closed after 5 s in the "tilt" position
4. The sunroof is then opened and the end position stored
5. The sunroof is then closed and the end position stored

Time required for initialization approx. 120 s.

Interruption In Power Supply

An interruption in the power supply does not require renewed "normalization". If the power supply is interrupted during initialization the entire procedure is invalid and the system must be re-initialized.

Deleting Initialization

The initialization is deleted under the following circumstances

1. Failure of the supply voltage during initialization
2. Hall sensor fault detected
3. Position implausible
4. Certain instructions in the diagnosis
5. Modified/changed vehicle coding
6. Coding data faulty

Scheme 252

Scheme 253

Anti-Theft Alarm System (DWA)

The Anti-Theft Alarm System in the E90 monitors the armed status of the complete vehicle. The doors, hood, trunk lid, emergency current siren, vehicle interior and the DWA/K-Bus are monitored. The control/operation of this system is distributed among several different control modules.

Scheme 254

The Roof Functions Center supplies terminal 30 and terminal 31 to the ultrasonic passenger compartment protection system (interior movement detector). The K-CAN and DWA bus connections for the ultrasonic passenger compartment protection system are looped through the FZD, which supplies ground to the DWA LED. The signal from the ultrasonic passenger compartment protection system is looped through for the DWA LED.

Ultrasonic Passenger Compartment Sensor (USIS)

Ultrasonic Passenger Compartment Protection System has been adopted from the E65 and adapted to the E90. The function of the anti-theft alarm system is integrated in the USIS.

The Footwell Module monitors the door contacts for the anti-theft alarm system. In the event of a change in the status, the FRM sends this information via the K-CAN, thus allowing the USIS to trigger the alarm.

The Junction Box Electronics Control Module monitors the trunk lid status in the central locking system. In the event of a change in the status, the JBE sends this information via the K-CAN, thus allowing the USIS to trigger the alarm.

The Car Access System 2 monitors the status of the hood contact switch. If the hood contact switch sends a signal, the CAS2 sends the corresponding information via the K-CAN and the USIS triggers the alarm.

Functions Of The Anti-Theft Alarm System

The anti-theft alarm system can be armed and disarmed at terminal 30. It is not possible to arm the anti-theft alarm system at terminal R or terminal 15.

Arming The Anti-Theft Alarm System

The anti-theft alarm system is armed from the driver's door lock barrel or by means of the remote control, together with the vehicle central arrest function. The following phases are implemented

1. Directly after arming Emergency current siren is armed and monitors its voltage supply Anti-theft alarm system starts monitoring of the DWA bus If the emergency current siren does not confirm the armed status, the DWA LED flashes to signal this status
2. 3 sec. after arming Door contacts, trunk lid and hood contact switches are adopted in the alarm table 3 sec. after they have signaled the "closed" status Faulty contacts are entered in the information memory and interpreted as closed but not adopted in the alarm table. They are not included in the evaluation for alarm triggering.
3. 3 sec. after arming or closing the last door, trunk lid or hood Initialization of the tilt alarm sensor starts (current position of the vehicle is determined and stored as a reference). Initialization of the ultrasonic interior motion sensor is started. As part of the initialization procedure, an ultrasonic field is built up in the vehicle interior and compared to the reference models. The sensitivity is then set corresponding to the positions of the windows and sunroof. NOTE: Opening the trunk lid during the initialization interrupts the procedure. Initialization is restarted after closing the trunk lid.
4. 20 sec. after closing the hood, trunk lid or last door Following its initialization, the ultrasonic interior sensor is adopted in the alarm table.
5. 30 sec. after closing the hood, trunk lid or last door Following its initialization, the tilt alarm sensor is adopted in the alarm table.

The tilt alarm sensor is masked out if no feedback telegram is received from it within 60 sec. after arming

Deactivating Tilt Alarm & USIS

It is advisable to deactivate the tilt alarm sensor and USIS in the following situations

1. Vehicle on ship transport
2. Vehicle on car transporter
3. Persons or animals in vehicle

Deactivation takes place by resetting the central arrest within 10 sec. after the central arrest or convenient closing function. Feedback is provided by the DWA LED lighting for 2 seconds.

Note. The tilt alarm sensor or ultrasonic passenger compartment sensor can be permanently deactivated by way of coding.

Disarming The Anti-Theft Alarm System

The anti-theft alarm system is disarmed by the "unlock" or "selective unlock" central locking functions.

An audible and/or visual signal can be output in connection with disarming corresponding to the country-specific version.

The DWA LED flashes for 5 min if an alarm was triggered during the time the anti-theft alarm system was armed.

If the system is disarmed during the alarm, the action is not acknowledged but rather the alarm is terminated.

Unlocking The Luggage Compartment

The tilt alarm sensor and USIS are blanked out if the luggage compartment is unlocked and opened on an armed vehicle since loading the vehicle could bring about a new vehicle status. The initialization procedure for the USIS and tilt alarm sensor is resumed 3 sec after closing the trunk lid.

Forced Disarming

The anti-theft alarm system is disarmed when a person remains in the vehicle and sets the vehicle central arrest function via the remote control.

The CAS2 recognizes the remote control if it is now inserted in its holder. The CAS2 sends the "locked" message via the K-CAN and the Anti-theft alarm system is disarmed.

Feedback From Anti-Theft Alarm System

When arming, the anti-theft alarm system provides feedback only when all doors, hood and trunk lid are closed.

Visual feedback is provided via the hazard warning lights or the DWA LED.

Feedback Via DWA LED

For the vehicle user, the DWA LED serves as an indicator showing the status of the Antitheft alarm system.

When flashing, the DWA LED is driven at a frequency of 0.5 Hz and the ON-interval is 60 ms.

When blinking, the DWA LED is driven at a frequency of 2 Hz.

DWA STATUS

Feedback Via Emergency Current Siren

Audible feedback during the arming and disarming procedure for the vehicle user is coded country-specific.

FEEDBACK VIA EMERGENCY CURRENT SIREN

Feedback Via Blinking Lights

Visual feedback in response to arming and disarming via the blinking lights serves as an indicator for the vehicle user.

The feedback is coded specific to the country version and/or model.

FEEDBACK VIA BLINKING LIGHTS

It is possible to place the remote control in the luggage compartment when the vehicle is locked and the luggage compartment open. Upon closing the luggage compartment, however the trunk lid is automatically opened again in order to avoid locking the remote control in the luggage compartment. In addition to automatically opening the trunk lid, the Anti-theft alarm system outputs an audible warning. The warning comprises a triple double-tone of the emergency current siren.

Door Contact Signals

The status of the door contacts is evaluated by the FRM and signaled to the USIS. The status of the individual door contacts is adopted in the alarm table 3 sec. after the status signal "door closed" is received by USIS. This means that an alarm can be triggered via a door that is already closed even if another door contact is still open.

The FRM evaluates the Hall sensors and makes this information available via the K-CAN to other bus users.

Trunk Lid

The status of the trunk lid contact switch is evaluated by the JBE and signalled to the USIS.

Initially, signals from the trunk lid contact switch, USIS are blanked out in the alarm table when the trunk lid is unlocked while the anti-theft alarm system is armed. The signals are also blanked out when the trunk lid is unlocked with the remote control with the anti-theft alarm system armed. The trunk lid contact switch is re-adopted in the alarm table 3 s after closing the trunk lid. The initialization procedure for the ultrasonic passenger compartment sensor and tilt alarm sensor is started if another door or the trunk lid is no longer open.

Hood

The status of the hood contact switch is evaluated by the CAS2 and signalled to the USIS. The status of the hood contact switch is adopted in the alarm table 3 sec. after the "hood closed" status message. If not engaged, the CAS2 interprets the hood contact switch as closed.

Note. A hood contact switch that was not coded correctly in the CAS 2 produces an implausible signal. The implausible signal triggers a false alarm.

The USIS senses and evaluated movements in the vehicle interior. The initialization procedure for the USIS is started 3 s after closing the hood, trunk lid and last door. The USIS is operational 20 s after initialization and is adopted in the alarm table.

Tilt Alarm Sensor

The tilt alarm sensor registers the vehicle rest position when it is armed and detects changes in the position, e.g. jacking up the vehicle. The tilt alarm sensor is integrated in the emergency current siren. The initialization procedure for the tilt alarm sensor is started 3 s after closing the last door and trunk lid. The tilt alarm sensor is operational 30 s after initialization and is adopted in the alarm table.

If no feedback telegram is received from the emergency current siren or tilt alarm sensor, this status is entered in the information memory of the anti-theft alarm system. The tilt alarm sensor is not adopted in the alarm table.

If the tilt alarm sensor detects vehicle movement, a corresponding signal is sent to the USIS. The anti-theft alarm system decides whether the movement is sufficient to trigger an alarm.

To ensure a false alarm is not triggered as the result of the vehicle rocking, the angle values for the longitudinal and transverse axis are determined every 90 ms. An alarm is triggered only if the vehicle remains in an inclined position for longer than approx. 1.5 s.

The alarm triggered by the tilt alarm sensor is stored in the ultrasonic passenger compartment protection system.

Self-Monitoring Of Emergency Current Siren

A self-monitoring facility that is activated immediately after the anti-theft alarm system has been armed is implemented in the emergency current siren. The emergency current siren monitors its own power supply and detects overvoltage, undervoltage and line break (open-circuit).

If the emergency current siren detects a tampering attempt, it sends a corresponding signal to the USIS, irrespective of whether the DWA bus is affected and triggers a stand alone alarm.

Line Monitoring - DWA Bus

The ultrasonic passenger compartment protection system and the emergency current siren are connected via the DWA bus. Immediately after arming the anti-theft alarm system, the DWA bus is monitored cyclically every 2 s.

The anti-theft alarm system sends a line monitoring request on the DWA bus to the emergency current siren.

The emergency current siren must respond within 100 ms. If no reply is received, the request for line monitoring is sent a further two times. If still no response is received, the Anti-theft alarm system triggers an alarm. The line monitoring facility is also active while the alarm is triggered.

The anti-theft alarm system measures the system voltage. To avoid false alarms, the line monitoring facility is switched off at a system voltage below 9 V. This avoids false alarms.

Alarm Output

If an alarm criterion is fulfilled with the Anti-theft alarm system armed, the alarm is output (triggered) audibly and/or visually corresponding to the country-specific coding.

Audible Alarm

The emergency current siren receives a signal via the DWA bus when the anti-theft alarm system in the ultrasonic passenger compartment protection system triggers an alarm.

The emergency current siren confirms receipt of the alarm request and triggers the audible alarm.

If the alarm request is not confirmed, the Anti-theft alarm system will repeat the alarm request up to eight times.

Corresponding to the country-specific coding of the emergency current siren, an intermittent or interval tone is generated. The audible alarm is interrupted immediately and without feedback when the anti-theft alarm system is disarmed.

Visual Alarm

Depending on the country-specific version, the following components of the outer lighting system can be activated for the visual alarm

1. Direction indicator lights
2. Low beam headlight
3. High beam headlight

When the anti-theft alarm system triggers an audible alarm, a visual alarm is simultaneously triggered for 5 minutes. The anti-theft alarm systems sends the "flash" request via the K-CAN to the FRM. In turn, the FRM activates the components of the exterior lighting system. The visual alarm cannot be extended by repeated alarm triggering.

The visible alarm is terminated immediately and without feedback when the anti-theft alarm system is disarmed.

Self-Contained/Integrated Alarm

The emergency current cycle triggers the self contained/integrated alarm if its lines are tampered with. If the DWA bus is also cut through, the USIS detects this situation by the absence of the reply from the emergency current siren. In turn, USIS triggers the visual alarm.

Panic mode represents an option for the vehicle user to draw attention by triggering alarm, e.g. when under threat from the outside or in the event of an accident.

Panic mode is initiated by pressing the trunk lid button on the remote control. the button must be pressed for longer than 2 s irrespective of whether the anti-theft alarm system is armed or not.

The alarm is terminated by pressing any button on the remote control. Panic mode is not stored.

If panic mode is initiated, the line is monitored during the entire duration.

The anti-theft alarm system sends the alarm request and expects the reply from the emergency current siren.

On completion of panic mode, the anti-theft alarm system assumes the setting that was selected prior to panic mode.

Alarm Termination

An alarm triggered for test purposes or inadvertently can be terminated by disarming the anti-theft alarm system or by inserting the remote control in its holder. The alarm is terminated immediately. No audible or visual feedback is output.

Scheme 255

Scheme 256

Electronic Steering Lock (ELV)

The Electric Steering Wheel Lock (ELV) feature was first introduced on the E52 (Z8). Since its initial introduction the system has been revised and was recently introduced on the E87 (available in Europe) plus will be available with the E90 as well. The purpose of feature is to electrically lock and unlock the steering column.

Advantages Of The ELV

1. Remote control "Key" similar to that used on the E65, in the form of a "bitless" key
2. An electronic fault and a mechanical fault must occur simultaneously
3. No steering wheel lock mechanism in knee impact area
4. The E90 can also be equipped with the Comfort Access option

Scheme 257

The CAS functions as the master controller and monitors the various driving or standstill situations of the vehicle, using speed sensor data, and is therefore also the control module that triggers/enables the unlocking (release) or locking action in the ELV.

Dynamic Stability Control (DSC)

The DSC module provides information pertaining to the wheel speed sensors to the CAS2

(DSC via PT-CAN - JBE via K-CAN - CAS2)

A redundant speed sensor signal is also provided directly to CAS2 by way of a direct connection from the DSC module to CAS2.

The JBE is the gateway module for transmitting the data from the DSC module to the CAS2.

Electric Steering Lock (ELV)

The ELV module is responsible for activating the mechanical components that lock and unlock the steering column.

Scheme 258

Safety Concept

A special safety concept is necessary in view of the special safety requirements of the system. The safety concept must ensure that the steering cannot be locked while driving.

As the master control module, the CAS2 evaluates all input signals, checks them and issues the enable signal to the ELV control module for the lock and unlock functions. The control unit of the electric steering lock system is therefore the executing component in the safety concept.

Electronic Function

The CAS2 monitors the various driving or standstill situations of the vehicle (signal from DSC) and is also the control module that triggers/enables the unlocking or locking action by supplying power and ground to the ELV. CAS2 changes the polarity signal provided to the ELV depending if the steering is to be locked or unlocked.

When CAS2 supplies a signal to the ELV a ground connection is applied first then power, the opposite occurs when the signal is removed. No power is applied to the ELV when the vehicle is not moving.

Unlocking the Steering

The following procedure is necessary to unlock the steering

1. Detection of a valid remote control/ID transmitter
2. Enable (release) of the unlock function
3. Unlocking the steering
4. Feedback
5. Switching off ELV module

Valid Remote Control

On vehicles equipped with the CAS2, the remote control must be inserted in its holder in order to check whether the remote control is valid for this vehicle.

Note. On vehicles equipped with the Comfort Access system, the ID transmitter must be located in the vehicle interior in order to check whether the ID transmitter is valid for this vehicle.

Enable (Release) Of Unlock Function

The power supply for the ELV is switched on after successfully checking the electronic vehicle immobilizer and receiving start authorization. Based on the status of the Hall sensor, the ELV module checks whether the steering is locked or unlocked. The status is sent via the CAS/K-bus to the CAS2.

The enable signal is issued after evaluating the following input signals

1. Vehicle speed signal
2. Terminal status
3. Hall sensor ELV.

Unlocking Steering

The ELV module starts the unlocking procedure and briefly activates the motor three times to move the lock pin in the unlock direction. The safety lever locks mechanically into the unlocked position to secure the unlocked steering column.

The steering is now unlocked and successful completion of the unlock procedure is detected by the status of the Hall sensor.

The steering wheel must be turned back and forth if this is not the case. The motor is again driven three times.

A Hall sensor registers the end position of the secured lock pin. The ELV module evaluates the Hall sensor and stops motor operation.

Feedback

The ELV module sends the "unlocked and secured" status to the CAS2, which stores the status of the ELV.

Switching Off ELV Control Module

The final item of information the CAS2 receives is the request to switch off the ELV. On receiving this request, the CAS2 switches off the power supply.

Locking Steering

The following procedure is necessary to lock the steering

1. Lock request to the CAS2
2. ELV module switched on
3. Locking the steering
4. Feedback
5. Switching off ELV control module

Lock Request

The CAS2 initiates the steering locking procedure when the remote control is removed from its holder.

The following conditions must apply in order to lock the steering

1. Vehicle speed < 1 km/h. The CAS2 receives this signal directly and redundant via the K-CAN from the DSC module.
2. Terminal 15 OFF
3. ELV Hall sensor status
4. Remote control/ID transmitter removed from plug-in slot
5. Central locking secured (terminal 0).

Note. In connection with the Comfort Access system, the lock function is initiated by detecting terminal 0.

ELV Control Module Switched On

The CAS2 switches on the ELV module. The Hall sensor of the electric steering lock is then checked along with the "lock" conditions. On successful completion of the check, the CAS2 issues the enable signal to lock the steering.

Locking The Steering

The ELV module activates a motor, which places a pretension on the "locking spring". The locking pin and safety lever are released so that the locking pin locks the steering. The ELV module detects the "locked and secured" position of the locking pin based on the Hall sensor.

The ELV module detects the "locked and secured" position of the locking pin based on the Hall sensor.

This status is sent to the CAS2 which stores the status of the ELV.

Switching Off The ELV Control Module

The CAS2 receives the request to shut down with the last telegram from the ELV module.

Scheme 259

ELV Mechanism

A locking lever with its position monitored by a sensor and a locking pin are the main components of the mechanical part designed to lock or unlock the steering column at the correct moment. The entire internal kinematic structure is designed such that a mechanical lock (locking lever) keeps the unlocked locking pin in position when no power is applied to the ELV.

Scheme 260

Scheme 261

From the "unlocked" position, the electric motor (7) begins to turn the gearwheel with controlled steps (3) and releases lock mechanism/lever.

The drive carrier with worm gear (2) is blocked by the locking lever (8). The nut (6) now begins to rotate.

Scheme 262

The nut (6) moves on the worm towards the locking lever (8).

Scheme 263

The locking lever (8) is now rotated by the control contour so that the drive carrier with worm (2) and locking pin (1) snap in position.

Scheme 264

The locking pin (1) is snapped into place with the mechanism in the locked position. The locking lever (8) rests on the drive carrier.

Wiper/Washer System

The wipe/wash system on the E90 is a conventional wipe/wash system. This means that the wiper motor is equipped with a return contact.

System Components

The following components are involved in the wipe/wash system

Scheme 265

1. Wiper motor with return contact
2. Washer fluid pump
3. Pump for headlight washer system
4. Heated water jets.
5. Control units
6. Relays: Steering column switch cluster Junction box control module (JBE) Dynamic stability control (DSC) Roof function center (FZD) Rain and driving lights sensor (RLS) Relay for headlight washer system Instrument cluster (IKE/Kombi)

Scheme 266

The Junction Box Electronics Control Module is the master for all wiper functions.

The relays for the wipe/wash functions are installed in the JBE. The relay for the continuous wipe function in Stage 1 is plugged in and the relay for Stage 2 soldered to the PC board.

A relay is installed in the Junction Box for the headlight washer system.

The Rain and Driving Lights Sensor is connected via LIN-Bus to the Roof Functions Center.

The Dynamic Stability Control makes available the vehicle speed signal and is the interface to the Steering Column Switch Cluster (SZL).

Wiper Switch

The wiper switch with the following functions is located in the steering column switch cluster

1. Intermittent wipe
2. Stage 1 and Stage 2
3. Windscreen washer
4. Switch for rain and driving lights sensor
5. Indicator for active rain and driving lights sensor

The wiper switch is an optical switch. The functions of the optical switch are described in the section entitled " STEERING COLUMN SWITCH CLUSTER " later in this section.

The interval switch is a four-stage switch.

Each switch stage produces different input values in the steering column switch cluster SZL. The input values are evaluated, for example, for setting the sensitivity of the rain and driving lights sensor.

The button for the rain and driving lights sensor is designed as a ground-switching button. It is required to switch on the rain and driving lights sensor. The LED on the stalk switch is illuminated when the rain and driving lights sensor is activated.

Wiper Motor

The wiper motor is designed for two speed stages and has a reset contact.

Pump For Windscreen Washer

The washer fluid pumps for washing the windscreen are mounted on the washer fluid reservoir. The pump is activated directly by the Junction Box Electronics Control Module.

Pump For Headlight Washer

A high pressure pump is used for the headlight washer system. The pump is activated by means of a relay in the junction box.

Heated Water Jets

Two heated water jets are used for the windscreen washer. The water jets feature a PTC resistor that limits the current intake itself.

Scheme 267

Steering Column Switch Cluster Failing

The JBE recognizes failure of the steering column switch cluster by the absence of the "wipe switch operation" signal via the K-CAN. The JBE then switches over to emergency operating mode.

Emergency operation consists of permanent wiper operation in stage 1. The wiper operates constantly as from terminal R. It cannot be switched off until the fault has been rectified. If the steering column switch cluster SZL fails during wiper mode, the wiper will continue to operate for 11 s in the set wiper mode and then switches over to emergency operating mode.

After emergency operating mode, the wiper is updated only after receiving a new message from the SZL and determining the wiper position via the reset contact.

Rain And Lights Sensor Failing

If the rain/driving lights sensor fails or is defective, the JBE undertakes the wiper control and switches to emergency operating mode. This emergency operating mode is an intermittent wipe mode dependent on the vehicle speed.

The following functions are switched on with the wiper switch

1. Automatic wipe with rain and lights sensor
2. Continuous wipe, Stage 1
3. Continuous wipe, Stage 2
4. Single wipe
5. Wash windscreen.

The signals of the wipe switch are sent from the steering column switch cluster via the F-CAN to the dynamic stability control. The signal is then transferred from the dynamic stability control via the PT-CAN to the Junction Box Electronics Control Module. The Junction Box Electronics Control Module evaluates the signals and activates the wiper motor.

Windscreen Wipe Function

The following functions are available for wiping the windscreen

1. Intermittent wipe in stages
2. Automatic Intermittent wipe
3. Continuous wipe, Stage 1
4. Continuous wipe, Stage 2
5. Single wipe.

Intermittent Wipe

The Intermittent wipe in stages only operates if the RLS system is defective. E90 will come with RLS standard. The interval can be set with the multi-stage switch. Four intermittent wipe stages are available. The time intervals depend on the set intermittent wipe stage and the vehicle speed.

The Junction Box Electronics Control Module calculates the time intervals and activates the wiper motor accordingly.

Automatic Intermittent Wipe

The automatic wipe function is activated by pressing the wiper stalk switch button at terminal R ON. When active, the "automatic wipe" function is indicated by the LED on the wiper switch. A single wipe cycle is additionally started.

Scheme 268

Wiper Stalk Switch

The rain and lights sensor sends a wipe request corresponding to the rain intensity. The roof functions center checks the rain and lights sensor every 20 ms to establish whether the wipe request applies. When the request is sent, the rain and lights sensor confirms this request via the LIN-bus. The roof functions center sends this request on the K-CAN.

The Junction Box Electronics Control Module evaluates the request and activates the wiper motor accordingly.

During the automatic wipe cycle, the wiper wiping frequency depends on the information provided by the rain and lights sensor and to vehicle speed.

The control of the wipe/wash system is integrated in the Junction Box Electronics Control Module.

Continuous Wipe Stage 1

The wipe motor runs at normal speed when Stage 1 is switched on with the wiper switch. The wiper motor switches from continuous wipe in Stage 1 to intermittent wipe if the vehicle speed is reduced down to standstill.

The continuous wipe function in Stage 1 resumes as soon as the vehicle speed is > 4 km/h.

Continuous Wipe Stage 2

The wiper blades are moved at double the speed in continuous wipe Stage 2. When the vehicle is stationary, continuous wipe Stage 2 automatically switched back to continuous wipe Stage 1. The wiper blades then move at normal speed.

Single Wipe

By pressing down the wiper switch, the flick wipe function is triggered for as long as the switch is pressed. On releasing the wiper switch, the wiper movement is completed to the park position of the wiper blades.

Wash Functions

The E90 features a specific wash function for the windscreen. The function is operated via the wiper switch.

Wash Windscreen

On pulling the wiper switch, initially the washer fluid pump is switched on followed by the windscreen wiper. The washer fluid pump remains switched on for as long as the wiper switch is pulled.

The signal is routed from the SZL to the Junction Box Electronics Control Module (JBE).

The JBE activates the washer fluid pump directly. After the pump is switched off, the wipers continue to operate for several wipe cycles in order to wipe the windscreen dry.

The JBE will no longer drive the washer fluid pump if the fluid level in the washer fluid reservoir is too low. The JBE receives the information necessary for this purpose from the washer fluid level sensor.

Terminal 50

The washer function is interrupted or not at all started while the vehicle is started.

If the windscreen washer function was interrupted, the started function is continued after the vehicle start procedure has been completed.

Headlight Washer System

The headlight washer system is switched on during the first wash cycle after terminal R ON and lights ON. Activation is then suppressed for 7 min. The headlight washer system is activated if the windscreen washer system is operated 5 times within the 7 minutes.

In response to the request from the Junction Box Electronics Control Module, the headlight washer system is switched on by means of a relay in the junction box.

The headlight washer system is no longer activated if the washer fluid level in the washer fluid reservoir is too low. The Junction Box Electronics Control Module receives the corresponding signal from the washer fluid level sensor.

The headlight washer system is not activated when blocking of the wipers is detected.

The water jets can be heated as from terminal 15 ON. The Junction Box Electronics

Control Module activates the water jet heating system via two separate outputs.

Activation is dependent on the outside temperature and whether the windscreen wipers are switched on. The Junction Box Electronics Control Module calculates the operating time of the water jets. The clock frequency for activation is 1 Hz.

HEATED WATER JETS REFERENCE

Park Distance Control

On the E90, Park Distance Control (PDC) is a distance warning system that provides both visual and audible information on the distance to the nearest obstacle when parking and driving out of spaces.

The distance to the nearest obstacle is measured by the four sensors in the rear bumper.

The distance is signalled audibly via the speakers in the rear of the vehicle. Signal tones increase as the distance to the obstacle decreases.

A permanent tone signal is output when vehicle is in close proximity to obstacles. The signal tones are produced and output by means of the existing audio system (RAD2 or CCC).

When the vehicle is equipped with navigation, the graphic distance signalling is shown on the Central Information Display (CID).

The PDC can be switched on and off by means of a button in the center console Switch Cluster (SZM).

The following changes/new features have been implemented compared to the predecessor models

1. Different speaker configurations (corresponding to equipment).

The following components are involved in the PDC system

Scheme 269

1. PDC control unit
2. Four Ultrasonic Sensors
3. Audio system (RAD2 or CCC w/speakers)

Scheme 270

Scheme 271

Control Unit

A 4-channel (rear only) PDC control unit is installed in the E90. Activation of the audible and visual distance signalling is through the RAD2 or CCC.

The PDC control unit is installed on the rear right in the luggage compartment and for U. S. applications the control unit has two connectors.

Scheme 272

Ultrasonic Sensors

The sensors used on the E90 offer additional benefits

Larger Range

The range of the new sensor is approximately 250 cm. The entire range of the sensors is used for visual distance signalling. The converter range is reduced to 150 cm at the rear for audible distance signalling.

Optimized Design

The length of the sensors in the E90 are approx. 50% of the previous sensor, which results in a reduced housing depth of the sensor. Due to the new design, the sensor is not decoupled in the component. The decoupling ring does not serve as a seal.

The installation of the decoupling ring is essential and ensures trouble-free operation.

Scheme 273

The Ultrasonic Sensors operate based on the echo-sounding principle.

Send Mode

The ultrasonic sensor behaves as a "speaker" in send mode.

By triggering electric pulses, the electronic circuitry of the ultrasonic sensor causes the piezoelectric crystal located on the inside of the outer diaphragm to move (conversion of electrical energy to mechanical energy).

The outer diaphragm vibrates in line with the resonance frequency and produces ultrasonic waves. The short pulse sequences (12 sinusoidal oscillations) hit an obstacle and are reflected.

Receive Mode

The ultrasonic sensor behaves as a "microphone" in receive mode.

After the outer diaphragm has settled (~ 1 ms), the ultrasonic sensor receives the ultrasonic waves reflected by the obstacle.

The outer diaphragm and the piezoelectric crystal oscillate and send the electrical pulses to the electronic circuitry of the ultrasonic sensor (conversion of mechanical energy to electrical energy).

Scheme 274

The electrically measured signal is digitized and transferred to the control unit, which processes the data to establish the distance to the obstacle is calculated.

Echo propagation time is calculated from the send start time and the time the incoming echo is received. Based on the known ultrasonic speed, the echo propagation time is a measure for the distance to the obstacle.

Activating System

The PDC must be switched on, by engaging reverse gear, in order to activate the distance signalling function.

The PDC receives the signal information via the K-CAN

1. Manual transmission vehicles - the Footwell Module reads the signal from the gearshift lever and makes it available via the K-CAN
2. On automatic transmission vehicles - the automatic transmission control unit sends the signal via the PT-CAN to the Junction Box Electronics Control Module, which makes the signal available via the K-CAN.

The PDC can also be activated by means of the button in the center console switch cluster. The signal from the button is received by the IHKA which transmits it via the K-CAN to the PDC.

Audible Distance Signaling

The distance is signalled audibly by means of the audio system, which receives the distance signals from the PDC via the K-CAN.

Both the RAD2 and the CCC make it possible to distinguish between left and right.

Visual Distance Signaling

Visual distance signaling can be displayed on the CID if the vehicle is equipped with a Car Communication Computer (CCC).

Scheme 275

Exterior Lighting

The standard exterior lighting system on the E90 consists of

1. Front headlights with: Side Light Low Beam Headlight High beam
2. Direction Indicator
3. Tail Lights
4. Brake Light
5. Reverse Light
6. Third Brake Light
7. Fog Lights
8. Front Direction Indicator Light Repeaters
9. Rain Light Sensor and Automatic Driving Lights Control The following exterior lighting system option is available on the E90: Bi-xenon Headlight (SA 522) in conjunction with Adaptive Headlight (SA 524)

Scheme 276

The Footwell Module (FRM) is the master control module for all exterior lighting functions.

All exterior light systems (headlights and side/parklights) are switched on and off via the light switch. Information to turn the lights on or off is supplied from the light switch directly to the FRM.

The SZL directly provides information to flash headlights, activate high beams or activate turn signal indicators to the FRM via a hard wired connection for this stalk.

In the "automatic" driving lights setting, the FRM indirectly receives information for switching the vehicle lighting on/off from the Rain Lights Sensor (RLS).

Signal path: RLS via LIN-BUS to FZD; FZD via K-CAN to FRM to headlights.

The hazard light switch is connected directly to the FRM.

The Junction Box Electronics Control Module provides a pass-through function for the signals from the SZL, which are transmitted on the F-CAN to the DSC module.

Junction Box (JB)

The power to the FRM is supplied from the Junction Box

The Car Access System provides ignition switch information to the FRM

The Roof Function Center transfers/routes the information from the RLS to the FRM via the K-CAN. The RLS provides information to activate/deactivate the headlights based on the level of exterior brightness.

Ultrasonic Passenger Compartment Protection Sensor (USIS)

If the alarm system is installed (Center installed accessory), in the event of a triggered alarm, a request is sent to the FRM to trigger a visual alarm by flashing the lights. Flashing of the lights in association with arming and disarming the alarm system can be set as part of the vehicle memory/individualization function using the diagnostic equipment.

Multiple Restraint System (MRS5)

In the event of a crash the MRS5 sends a request to the FRM to activate the hazard lights and illuminate the interior lights

Exterior Lighting Functions

Side Lights, Low Beam and High Beam are activated as follows

EXTERIOR LIGHTING FUNCTIONS REFERENCE

Automatic Headlamp Control

The driving lights are switched on together with the side lights by the automatic driving lights control system, activation of the lights is based on input from the RLS depending on the ambient lighting conditions (tunnel, twilight, rain or snow). The function is activated by having the light switch in the Auto headlamp position.

In the event of a malfunction with the RLS the FRM will illuminate the headlamps.

Note. The automatic headlamp control cannot serve as a substitute for personal judgement in determining when the lamps should be illuminated. As an example the system can not detect fog and should be activated manually.

On vehicles equipped with iDrive the sensitivity of the lighting activation point can be adjusted by selecting Vehicle Settings - Lighting - Auto Headlamps.

Fog Light

Foglights are activated by pressing the foglight button; side/park lights or low beam headlamps must be illuminated in order to activate the foglamps.

Directional Indicators

The front and rear turn signal indicators are activated via the turn signal stalk on the SZL, an optical switch.

A defective bulb in the front or rear indicator lights will result in the remaining lights flashing at double the normal rate. If a repeated light is defective this will have no impact on flash rate.

The one touch function will flash/activate the indicators lights three times. The function can be modified via personal profile/individualization/vehicle memory.

Hazard Lights

The hazard lights are activated by depressing the hazard light switch located in the center of the dash. The turn signal indicators have priority if the hazard flashers were activated first. The hazard flashers have priority if the turn signal indicators are active first.

If equipped with an alarm system the hazard lights are flashed for up to 6 minutes if an alarm is triggered and the alarm is not switched off. The FRM receives the request via the K-CAN from the USIS module.

The FRM provides information to the instrument cluster via the K-CAN to activate the audible indicator as well as the visual indicator.

Upon activation of the central locking function CAS2 supplies a signal to the FRM via KCAN to flash the hazard lights to indicate that the vehicle is locked. The visual feedback can be deactivated in the personal profile/vehicle memory settings.

Tail Lights/License Plate Lights

In the event of a malfunction the lamps in the brake light chambers are used as a substitute for the taillight. The bulbs are dimmed by means of a PWM signal in order to provide a substitute tail light operation.

Brake Lights & Brake Force Display

The brake light switch is power by a 5V signal from the CAS2, with terminal R ON.

1. Brake force display is standard on the E90 and is activated
2. Speed > 5 Km/h
3. Brake deceleration above 5 m/s2

Reverse Lights

On vehicles equipped with an automatic transmission, the signal for activating the reverse light is obtained by the FRM from the EGS module via PT-CAN. On vehicles equipped with a manual transmission the FRM obtains the signal from the reverse gear switch.

Lamp Monitoring

The Footwell Module (FRM) monitors all of the exterior lighting system with the lights switched on or off, as long as terminal 15 is active.

Cold Monitoring with Lights OFF

Cold monitoring is based on measuring the current of the individual lamp outputs. The current pulse used for measurement purposes is so short that the lamps are not illuminated. The FRM evaluates the individual lamp outputs to establish whether there is a line break or a lamp bulb is defective.

The number of current pulses is increased significantly during the first 4 s after terminal 15 ON to check whether the lamps are in working order before setting off. This function is referred to as the pre-drive check. The number of pulses is then reduced after the predrive check. Power is then applied to the lamps every 1.5 minutes.

The raised (3rd) brake light is not included in the cold monitoring system. The LEDs of the brake lamp react too fast to the current pulse and would consequently light up.

The bi-xenon headlight is also not included in the cold monitoring. Legal regulations prohibit the current pulse to the bi-xenon headlight.

Hot Monitoring with Lights ON

Hot monitoring is based on measuring the current of the individual lamp outputs. The lamp current is used to detect an overload or interruption (break).

Pathway/Follow Me Home Lighting

The lighting feature is activated by way of the headlight flasher position on the SZL stalk.

Bi Xenon Headlights

The Bi Xenon headlights are only installed on the E90 in conjunction with the Adaptive Headlight Control System.

Scheme 277

Adaptive Headlight Control

In conjunction with the Bi-Xenon headlights an Adaptive Headlight control system is also included on the E90.

The function of the Adaptive Headlight Control system is to provide an enhanced lighting path as the vehicle travels through a turn, plus reduce the risk of excessive glare to on coming traffic. The adaptive headlight control allows the headlights to rotate slightly as the front wheels turn.

Scheme 278

The Car Access System 2 provides ignition switch information to the FRM.

The control for the Adaptive Headlight is incorporated into the Footwell Module.

The FRM is connected to

1. K-CAN
2. PT-CAN
3. LIN-bus.

Note. The FRM is not a gateway for the PT-CAN, however, it does serve as a gateway between K-CAN and LIN-bus.

The FRM can receive data via the PT-CAN as well as the K-CAN and LIN-Bus, however it only transmits data via K-CAN and LIN-Bus.

In the event that the FRM is replaced the VIN must be entered and the module coded to the vehicle plus an adaptation process must be completed or the Complete adaptive headlight control function will not be active.

The dynamic stability control sends signals relating to the yaw rate and vehicle speed to the FRM for the operation of the Adaptive Headlight Control function.

The signals that are sent via the F-CAN pass-through the JBE, making it possible to transmit the steering angle data from the steering column switch cluster to the FRM.

Signal Path: Steering angle sensor in SZL via F-CAN to DSC; DSC to FRM via PT-CAN

Rain and Light Sensor (RLS)

The rain and light sensor is incorporated in the base of the rearview mirror. The signals from the RLS are used to switch on the automatic driving lights and activate the Adaptive Headlight Control function in the FRM.

The Roof Functions Center is the gateway for the RLS, and transfers the LIN-Bus signal of the RLS via the K-CAN to the FRM.

The USIS transmits the signal for the visual alarm of the anti-theft alarm system via the KCAN to the FRM.

Multiple Restraint System 5 (MRS5)

The MRS5 supplies a signal to the FRM in the event of a crash.

Bi-Xenon Headlight

The bi-xenon headlight control unit is mounted on the bi-xenon headlight and supplies the power and ignition voltage for the bi-xenon light bulb which is integrated in the swivel section of the adaptive headlight.

The zero position Hall sensor registers the zero position of the swivel module and the stepper motor provides the swivel movement of the swivel module.

A separate stepper motor is installed for the headlight vertical aim control.

The headlight can be replaced, however headlight-specific coding is necessary for the respective stepper motor controller. If this adaptation is not performed, the function will appear to operate, but not correctly.

The swivel range and zero point can vary from vehicle model to vehicle model and the bixenon headlight can have a different status! The headlights must be adjusted and checked.

Stepper Controller

The stepper motor controller is mounted on the side of the bi-xenon headlight and controls/ monitors the movement of the stepper motors for the adaptive headlight and the vertical aim control function.

The component can be replaced, however after replacing the stepper motor controllers, it is necessary to store the vehicle identification number and enter headlight related coding in the stepper motor controllers.

The complete adaptive headlight function will not be operative without this adaptation. Particular care must be taken when replacing the stepper motor controllers to ensure that the housing gasket of the stepper motor controller is fitted and seals correctly.

Directional Indicator/High Beam Switch

The SZL contains the direction indicator/high beam switch and provides this signal directly to the FRM via a hard-wired connection.

DSC Sensor

The DSC Sensor provides information pertaining to the yaw of the vehicle about the vertical axis

Rotation Rate Sensor

The rotation rate sensors supply the signals for the vehicle speed via DSC to the FRM.

Steering Angle Sensor

The Steering Angle Sensor is integrated in the SZL, is an optical sensor, and makes available data relating to the steering wheel angle.

Front And Rear Ride-Height Sensors

The ride-height sensors are installed on the front and rear axle.

The signals of the ride-height sensors are used for the headlight vertical aim control and are evaluated by the FRM.

Brake Pedal Switch

The signal of the brake pedal switch is used by the FRM to adjust for the headlight vertical aim control.

Headlight Rotation

In order for the headlights to rotate slightly as the front wheels are turned, a stepper motor is incorporated into the headlight assembly/swivel module. The FRM controls the amount of rotation based on the following information

Scheme 279

1. Steering angle
2. Road speed
3. Yaw rate.

Under normal driving conditions up to a speed of approx. 40 km/h, the adaptive headlight is controlled by the data from the steering angle sensor.

The information from the yaw rate sensor is included in the calculation for headlight rotation

1. At speeds greater than approx. 40 km/h
2. In the event of vehicle oversteering or understeering
3. A vehicle tending to yaw.

The adaptive headlight rotation function is deactivated in the event an oversteering, understeering or yawing condition is detected by means of the steering angle sensor and the yaw rate sensor. If the adaptive headlight function is deactivated the stepper motor/swivel module returns to its zero position.

In normal operation the Adaptive Headlight Control function allows the front headlight to rotate slightly as the vehicle moves through turns.

Scheme 280

The transition point of light/dark must be above the center line of travel when the vehicle is in a turn to reduce the risk reduce the risk of excessive glare to on coming traffic.

It is the responsibility of the stepper motor controller based on information received from the FRM via LIN-Bus, to control and monitor the stepper motors of each headlight plus the vertical aim control of the respective bi-xenon headlight.

The stepper motor controller performs the following functions

1. Receiving and evaluating the data sent from the FRM via the LIN-bus: Reference run Target position commands Diagnosis requests
2. Output control of the stepper motors
3. Zero position acquisition of swivel module
4. Reference run of swivel module
5. Position feedback of swivel module to footwell module
6. Diagnosis
7. Feedback of diagnosis data to the footwell module.

The FRM in its function as the central control unit for the adaptive headlight sends signals to the stepper motor controllers every 20 ms.

Scheme 281

Scheme 282

Steering Column Switch Cluster

The functions of the Steering Column Switch Cluster (SZL) are

1. Detecting steering angle and steering speed
2. Detecting the controls in the multifunction steering wheel (MFL)
3. Detecting switching signals in the steering column switches
4. Sending and receiving information to/from the interlinked control modules.

Scheme 283

Note. The steering column switch cluster SZL can only be replaced as a complete unit. The coil spring assembly is installed on the steering column switch cluster which can be removed and individually replaced.

The Electronic Steering Column Switch Cluster module contains a processor, power supply and the following interfaces

1. F-CAN
2. Optical switches
3. Electrical switches.

The optical sensor for measuring the steering angle is integrated in the pc-board of the control module.

F-CAN Link

The DSC control module is connected via the F-CAN to the SZL and serves as the gateway for the SZL, allowing data from the SZL to be distributed to the other control modules.

All diagnosis functions take place via the DSC control module.

There is no fault code memory in the SZL, since the SZL cannot communicate directly with the BMW diagnosis system.

Detection of Steering Angle and Steering Speed

The steering column switch cluster must detect the steering angle and steering speed information as the basis for calculating various functions in the DSC. Additional information such as the absolute steering angle or the steering wheel rotation information is calculated by the SZL

Scheme 284

The optical steering angle sensor is able to detect a steering angle of - 180°/+180°.

In order to measure the steering angle a "code"' disc rotates as the steering wheel is rotated. An LED and fibre optics unit illuminate the code disc from above and based on the pattern on the code disc, the light from above reaches the bottom receiver/camera only in certain areas. The light pulses received by the receiving unit are converted to electrical pulses by the sensor.

The pattern (1) on the disc changes in 2° increments, by evaluating the linear track (2) the steering angle can be defined to 0.1°

As the steering wheel is rotated the information contained in the pattern on the code disc (1) as well as the on linear track (2) changes. The changing information is "decoded" by the optical receiver and converted to electrical pulses to define the angle that the steering wheel has been rotated. Relative steering angle (°180°)

Scheme 285

1 = Pattern on Code Disc 2 = Linear Track

Scheme 286

Relative Steering Angle (+/- 180°)

The relative steering angle indicates the angle position of the steering wheel. The information relating to the relative steering angle is always retained even when power to the control module is disconnected. Renewed zero point adjustment/calibration is necessary only after the steering column switch cluster SZL has been replaced. DSC module is reprogrammed/replaced or after competing any repairs on the steering wheel/steering column.

Absolute Steering Angle

The absolute steering angle is a calculation based on the relative steering angle and steering wheel rotation information. The absolute and relative steering angle are defined during the zero point adjustment of the steering column switch cluster. The SZL detects each position of the steering wheel over the entire steering lock range. The precondition before any zero point adjustment procedure is that the wheels and steering wheel are set in the straight-ahead position.

Detecting Controls Of Multifunction Steering Wheel

The voltage signals of the buttons on the multifunction steering wheel are routed via the coil spring to the SZL. The SZL evaluates the voltage signals and sends the information to the corresponding control units.

The connections of the Steptronic switches, horn and the driver airbag are wired directly via the coil spring to the corresponding control units. This information is therefore not evaluated in the SZL.

Detecting the signals of the steering column switches Optical switches are used in connection with the steering column stalks on the E90. Optical sensors detect the stalk position and makes this information available to the SZL.

Direction Indicator/High Beam Switch

The signals of the direction indicator and high beam switch are monitored by the SZL and transferred via three voltage-coded lines to the FRM. Only information relating to the switch positions is transmitted.

The signals of the on-board computer button and the rocker switch are transferred via a line from the SZL to the Instrument Cluster.

The functions in the respective switch positions are defined in the control modules.

The signals of the wiper switch are calculated directly in the SZL and transferred via the F-CAN to the DSC and to the Junction Box Electronics Control Module

Cruise Control Switch

The signals for the DCC or ACC systems are made available to the LDM. The data is transmitted via the F-CAN to the DSC. From the DSC the data are forwarded via the PTCAN to the LDM.

Signal Flow

The acquired and calculated data of the SZL are mainly transferred via the F-CAN to the corresponding control module.

The information for diagnosis is therefore also transferred via the F-CAN to the DSC. The DSC establishes the communication interface with the BMW diagnosis system. The SZL cannot be addressed directly via the BMW diagnosis system.

The DSC must be coded after replacing the steering column switch cluster. The coding data is then transferred from the DSC to the SZL.

Steering Column Switches

The settings of all steering column stalks are determined optically.

Function

Depending on the steering column stalk, there are three or four LEDs on the outside and one optical receiver (LDR light-dependent resistor) on the inside of the steering column housing of the steering column stalk. A shutter is provided on the steering column stalk which, when in rest position, is located between the center LED and the LDR. As a result, the shutter blanks out the light of the center LED when in rest position.

Scheme 287

As soon as the steering column stalk is moved, the shutter moves up or down and one of the outer LEDs is covered. The LEDs are never activated together but always clocked one after the other. In this way, the electronic SZL module can detect which LED is currently blanked out. The function can be monitored by measuring the current at the LED.

The data from the buttons and thumbwheels in the steering column switches is converted to a voltage signal and either routed to the SZL and distributed to the corresponding control modules (wiper switch - JBE) or forwarded directly to other control modules (Turn indicators/high beam - FRM).

Locking

To avoid damaging the coil spring assembly, it must be set to the correct position when dismantling the steering wheel and coil spring assembly.

Scheme 288

The front wheels and steering wheel must be set to the straight-ahead position as the prerequisite for disassembly. During disassembly of the steering wheel, the load on the lock pin of the coil spring assembly is relieved and the pin can lock in the straight ahead position.

When the steering wheel is reinstalled, this arrangement ensures that the coil spring is not damaged when the steering wheel is turned to full left and right lock.

Scheme 289

Scheme 290

Outside Mirror

The following outside mirror functions are possible

1. Mirror adjustment in up/down and left/right directions
2. Mirror heating
3. Mirror folding function
4. Electrochromatic mirror
5. Outside mirror with memory function
6. Automatic parking function
7. Manual adjustment
8. Motor protection by repeat interlock.

Detecting Position of Outside Mirrors

The outside mirrors have two potentiometers for mirror adjustment, each potentiometer receives a 5 V supply from the electronic mirror module. The defined values of each potentiometer is stored in the FRM for the memory function.

Mirror Heating

The mirror heating is activated with of terminal 15 ON, by the FRM and the corresponding information is passed on to the electronic mirror module via the LIN-bus.

The Instrument Cluster makes available the outside temperature value via the K-CAN. The Junction Box Electronics Control Module provides the information for the wipers via the K-CAN.

The percentage of switch-on time is calculated from both values in the FRM.

MIRROR HEATING REFERENCE

The percentage of increase is retained for 300 s after the wiper is switched off.

The maximum electric heating output is 18 W that is set by means of voltage and current measurement in the mirror.

Undervoltage

The electronic mirror module switches off the mirror heating in the event of undervoltage, which has a positive effect on the charge balance of the battery. The cutout threshold is at 10.8 V.

The electronic mirror module switches on the mirror heating again once a voltage of 11.6 V is provided.

During the start procedure, the starter outputs the "terminal 50 ON" status and the mirror heating is switched off during this period of time.

Mirror Folding Function

The folding function is controlled by the Footwell Module (FRM). When the mirror folding switch is pressed, the driver's door switch cluster evaluates the request and transfers it to the FRM.

The FRM receives the request via the LIN-bus. Both outside mirrors are folded in towards the vehicle thus reducing the vehicle width.

The outside mirror folding function is also possible in connection with the convenient closing function. The outside mirrors are activated at the same time as the rear power windows. The Car Access System 2 provides the signal necessary for this purpose.

Electrochromatic Outside Mirrors

The automatic dip function of the outside mirrors is dependent on the setting of the interior rear-view mirror. The function is available with terminal 15 ON.

The interior rear-view mirror sends the request to dip the mirrors to the Roof Functions Center via the LIN-bus. In turn, the Roof Functions Center makes the request available on the K-CAN. The FRM sends this request via the LIN-bus to the outside mirrors.

The electronic mirror module controls the dip function of the outside mirrors.

Outside Mirror With Memory Function

The outside mirror features a memory function that is stored in the FRM. Three memory locations are available for this purpose: They are

1. Current position when leaving the vehicle
2. Memory position of memory button 1
3. Memory position of memory button 2

Up to three personalized remote controls are possible per vehicle.

When the vehicle is locked using the remote control, the current mirror position is stored in the memory location for the key memory of the remote control currently used. As a result, the mirror position last set, referred to the remote control used, is always reassumed when the vehicle is unlocked.

Storing Memory Position

The position of the outside mirrors is stored in the FRM by pressing the "M" button followed by pressing one of the memory buttons within 7 s. The driver's seat module evaluates the memory buttons and sends this information via the K-CAN.

Calling Up Memory Position

When the memory button is pressed, the driver's seat module receives the request to adjust the outside mirrors to the memory position.

The driver's seat module sends this request on the K-CAN. The FRM evaluates the request and activates the memory position.

Automatic Parking Function

The outside mirror on the front passenger's side is swivelled downward when reverse gear is engaged so that the curb can be easily viewed. The automatic parking function is activated under following conditions

1. Terminal 15 ON and
2. Reverse gear signal
3. Mirror selector switch set to driver position
4. Towing hitch must not be active.

Manual Gearbox

The FRM receives the signal via the reverse gear switch. This switch refers to ground and sends out a low signal when reverse gear is engaged.

Automatic Gearbox

The FRM receives the signal via the K-CAN. The automatic transmission control unit then makes this signal available.

Folding Mirror Manually

The outside mirrors can be folded in or out manually. The mirrors could loose their set position when folded in or out manually. It may be necessary to repeat the fold-in/fold-out function for the mirrors to find the set position.

Motor Protection By Repeat Interlock

The outside mirrors feature a repeat inhibit function to avoid thermal overheating by frequently folding the mirrors in and out. The motors cannot be activated for 180 s when the repeat inhibit is active.

Components Of Outside Mirror Function

The following components are installed in the E90 for the purpose of operating the outside mirrors

1. Driver's door switch cluster with Outside mirror adjustment switch Outside mirror selector switch LIN-bus link
2. Outside mirrors
3. Footwell Module
4. Junction Box Electronics Control Module
5. Components for comfort/convenience function Car Access System 2 Lock cylinder, driver's door Remote control receiver in interior rearview mirror

In connection with the Low outside mirror, the adjustment motors are connected directly to the driver's door switch cluster.

In connection with the High outside mirror, the adjustment motors are connected via the electronic mirror module.

The electronic mirror module is connected via the LIN-bus to the driver's door switch cluster.

The driver's door switch cluster is connected via the LIN-bus to the FRM and therefore also to the vehicle electrical system.

Scheme 291

Scheme 292

Seat Heating Module

The seat heating is operable as from terminal 15 ON. The junction box control unit determines what type of seat module is installed in the vehicle. It sends a corresponding query via the K-CAN for this purpose. Since the seat heating module is not connected to the K-CAN, only the driver's seat module with memory function can respond to the query. The junction box control unit must register a response within 200 ms. If the response fails, the junction box control unit undertakes control of the seat heating system.

On vehicles with a seat heating module, the junction box is responsible for converting the K-CAN telegram with switch information to a PWM signal for the seat heating module. The seat heating module activates the seat heating systems corresponding to the setting.

The seat heating function is available as from terminal 15 ON and activation of the seat heating module. The seat heating module is connected to terminal 30 for the load current. After the seat heating button has been pressed, the center console switch cluster routes the request to the automatic climate control system. As a link element, it sends the requests via the K-CAN to the junction box control unit. In turn, the junction box control unit sends a pulse width-modulated signal to the seat control unit. The pulse width depends on the required heating output stage.

The control unit receives the PWM signal corresponding to the temperature setting for the seat heating module. The seat heating module regulates the seat heating to the temperature specified by the junction box control unit.

The seat heating module determines the temperature by means of an NTC resistor in the heating mat of the seat cushion.

Seat Module, Driver's Side

The driver's seat module is connected to the K-CAN on vehicles with memory function. The driver's seat module evaluates the telegrams with the switch information and correspondingly controls the seat heating. The driver's seat module determines the set temperature by means of the NTC resistor in the heating mat of the seat cushion. A fault in the seat heating system results in a corresponding entry in the fault code memory of the driver's seat module.

Seat

With the exception of the driver's seat module with memory function, the seat settings are implemented directly via the seat adjustment switches. Adjustment is possible as from terminal 30. The blocking detection function for the motors is located in the junction box control unit. For this purpose, the motor current is registered and motor blocking is detected above a defined current threshold.

Driver's Seat Module With Memory Function

The seat adjustment switches are also read directly in connection with the driver's seat module with memory function but in this case by the driver's seat module with memory function itself. The seat adjustment switches supply a defined voltage corresponding to the request. Based on these voltage values, the driver's seat module determines what motor it must activate. Activation takes place via the relay in the driver's seat module until the seat adjustment switch is released or the end of the adjustment range is reached.

The Hall sensors in the adjustment motors supply Hall pulses which are evaluated by the driver's seat module with memory function. The seat position is determined based on the Hall pulses. This function is used not only to detect the end stops but also to store the memory position of the driver's seat.

Blocking of a motor is detected by means of the current measurement function integrated in the driver's seat module. In this case, the relays are no longer actuated thus shutting down the motors. The memory setting for this motor is inhibited until the motor is no longer blocked.

Lumbar Support

The lumbar support setting supports the spinal column and provides a more relaxed seating position for driving. The lumbar support function was adopted from the E46 and adapted to the seat of the E90.

Backrest Width

The backrest width adjustment is available only in connection with the sports seat. The function is located in the electronic circuitry in the valve block for the backrest width adjustment. The width of the backrest can be adjusted as from terminal 30.

When the backrest width adjustment switch is pressed to reduce the width of the backrest, the electronic circuitry in the valve block receives a low signal and correspondingly control the pressure control valves.

At the same time, the pump motor is activated and fills the two backrest width cushions on the left and right in the backrest.

To widen the backrest width, the pressure control valves are activated and the backrest width cushions are emptied.

Memory Function

The memory function for the driver's seat can be activated as from terminal R ON. Two memory positions and the current seat position can be stored. By pressing the memory button "M" followed by pressing button "1" or "2", the current position of the driver's seat is assigned to the pressed button. At the same time, the current position of the outside mirrors is also assigned to the pressed button. The information for storing the outside mirror position is sent by the driver's seat module via the K-CAN.

Note. The memory position of the outside mirrors is stored in the Footwell Module.

Center Console Switch Cluster

The switches for the seat heating are integrated in the center console switch cluster. They are designed as 3-stage switches.

The first switch stage switches on the seat heating with maximum heating power. The medium heating setting is activated after pressing the button a second time. The seat heating with the lowest heating output setting is switched on in the third switch stage.

The seat heating is switched off by pressing the button again or pressing it for longer than 1.2 s.

The center console switch cluster is connected by means of a ribbon cable to the air conditioning control unit (IHKA). The control unit makes the connection to the K-CAN.

The JBE features a control output each for the driver's and front passenger's seat heating. The signal sent by the JBE is pulse width modulated. The signal frequency is 25 Hz.

Note. The JBE undertakes the control of the driver's seat heating only when no driver's seat module with memory function is installed.

The seat heating module evaluates the signal from the junction box control unit. The seat heating module is connected by means of three connectors. One connector establishes the connection to the vehicle. The other two connectors are responsible for connecting the seat heating.

The driver's seat module is installed when the seat is equipped with electrical adjustment and a memory function. The seat module therefore receives the information via the K-CAN for controlling the seat heating. The seat module also evaluates the memory buttons and the seat adjustment switches.

The requests from the memory buttons for the outside mirrors are made available via the K-CAN. The seat memory setting is stored in the seat module.

The requests from the seat adjustment switches are executed directly by the seat module.

Scheme 293

Scheme 294

Seat Heating

The seat heating consists of a heating mat in the backrest and in the seat cushion. The heating mats form a single-circuit system. An NTC resistor is located in the heating mat of the seat cushion to control the temperature of the seat heating system. The seat heating is operable as from terminal 15 ON.

Scheme 295

Scheme 296

Scheme 297

The electrically operated roller sun blind features the following possible functions

1. Rear sun shade up and down End position recognition Relieving tension in rear sun shade Motor protection
2. Sleep mode
3. Child lock
4. Undervoltage

Switch-On Conditions

The rear sun shade can be operated as of "Terminal R ON" and is coupled to the enable for the Power Windows. The Car Access System 2 issues the enable via the K-CAN.

The rear sun shade can be operated only when the power window function is enabled. The enable is also dependent on the country specific version and the status of the door contact.

Signal Path

The SZM evaluates the signal from the control button and forwards it to the IHKA. The IHKA transfers the signal to the K-CAN and sends it to the junction box control unit. In turn, the junction box control unit activates the motor for the rear sun shade.

End Position Recognition

The motor blocks and the movement of the rear sun shade stops in the end position. The junction box control unit recognizes the end position by the increasing current and switches off the motor.

Relieving Tension In Rear Sun Shade

The rear sun shade is briefly reversed for approx. 20 ms in order to relieve the tension as fast as possible after blocking. This function protects the drive unit and mechanism of the rear sun shade.

Motor Protection

To protect the motor, the maximum activation time of the motor is limited to approx. 10 s.

The rear sun shade has no electronic anti-trapping function. The mechanism and drive units are designed such as to rule out any danger for the occupants posed by excessively high forces.

Child Safety Lock

The child safety lock is enabled or disabled by means of a button located in the driver's door switch cluster. It is not possible to operate the electric rear sun shade when the child safety lock is enabled.

Current operation of the rear sun shade is not interrupted when the child safety lock is enabled.

Operation of the rear sun shade is disabled if the system voltage drops below 9.0 V. Operation of the rear sun shade is enabled again with a system voltage higher than 9.5 V.

Current operation of the rear sun shade is not interrupted by the undervoltage protection facility but rather the procedure is completed.

Sleep Mode

The current position of the rear sun shade is stored in the JBE as soon as the vehicle assumes sleep mode.

The following components are involved in operation of the rear sun shade

1. Button for rear sun shade
2. Control units Integrated automatic climate control Junction Box Electronics Control Module
3. Rear window sun shade motor.

Scheme 298

Control Button

The control button is included in the center console switch cluster and switches to ground.

Scheme 299

Integrated Automatic Heating And Air Conditioning Control/Automatic Climate Control

The integrated automatic heating and air conditioning control/automatic climate control receives the signal from the control button and transfers it to the K-CAN.

Junction Box Electronics Control Module

The Junction Box Electronics Control Unit contains the motor drive function for the electric rear sun shade.

Rear Sun Shade Motor

The motor is designed as a DC motor and moves the two lifting arms of the rear sun shade in the UP or DOWN direction.

Scheme 300