Distance Systems, Cruise Control (Service Techniques) BMW M3 E90

Introduction

The BMW 1-Series, 3-Series and X5 can be equipped with option 322 "Comfort Access".

This comfort system has been derived from the BMW 7-Series.

From 09/2005, Comfort Access will also be introduced to the BMW 5-Series and BMW 6-Series. The system has been taken from the BMW 3-Series, albeit with a few modifications.

With Comfort Access, an ID transmitter is needed instead of the usual remote control. The ID transmitter also performs standard remote control functions.

Comfort Access can be used to carry out the following functions

1. Passive Entry Opening the vehicle or luggage compartment without actively using the ID transmitter
2. Passive Go Engine start without actively using the ID transmitter
3. Passive Exit Closing the vehicle without actively using the ID transmitter

Comfort Access prevents an ID transmitter being disabled accidentally.

The CAS control unit is the master control unit for all functions carried out via Comfort Access. Vehicles with Comfort Access are fitted with a CA control unit.

New or modified features on E90, E91, E92 compared to E81, E87, E93

1. The detection range of the interior aerials has been modified as a consequence of the different vehicle design.
2. The remote control (FBD) receiver is integrated into the aerial amplifier. (E81, E87, E93: FBD receiver integrated in interior mirror)

New or modified for the E60, E61, E63, E64

1. The outside door handle electronics is on the reverse of the door handle mounting bracket.
2. The CA control unit is installed in the carrier behind the glove compartment.

Brief description of components

The following components are described for Comfort Access

1. Interior and exterior aerials Different aerials are required for communication with the ID transmitter: Interior and exterior aerials The number of aerials depends on the model concerned: INTERIOR AND EXTERIOR AERIALS DIFFERENCE CHART Interior aerials E60 E61 E63 E64 E70 E81 E87 E90 E91 E92 E93 Front centre console x x x x x x x x x x x Rear centre console x x x x x x x x x x x Rear window shelf (parcel shelf) x - x - - - - - - - - Back of rear seat - x - - - - - - - - - Luggage compartment, middle x - x x - x x x x x x Luggage compartment, right - - x x x - - - - - - Luggage compartment, left - - - - x - - - - - - Luggage compartment, load edge - x - - - - - - - - - Exterior aerials E60 E61 E63 E64 E70 E81 E87 E90 E91 E92 E93 Rear bumper, left x - x x - - - - - - - Rear bumper, middle - x - - x x x x x x x Outside door handle electronics 4 4 2 2 4 2 2 2 2 2 2 The aerials emit 125 kHz radio signals which are evaluated by the ID transmitter.
2. Outside door handle electronics The number of outside door handle electronic units depends on the model concerned (see table above). The 3 sensors in the outside door handle electronics send the following signals to the CAS control unit and the CA control unit: Unlock: When a hand reaches into the handle recess via capacitive sensor 1 Unlock: When a hand pulls on the outside door handle via tension sensor (redundant to capacitive sensor 1) Locking and deadlocking: On contact with the sensitive area of the door handle via capacitive sensor 2 A built-in aerial also sends radio signals in order to check for an ID transmitter located on the outside of the driver's door or front-passenger door. E70, E81, E87, E90, E91, E92, E93 The outside door handle electronics are installed in the outside door handle. E60, E61, E63, E64 The outside door handle electronics are behind the grip recess plate.
3. ID transmitter The ID transmitter evaluates the signals from the aerials. It also sends high-frequency radio signals to the FBD receiver. Inserting the ID transmitter into the slot deactivates all Comfort Access functions.
4. Remote control receiver for remote control services E64, E81, E87, E93 The remote control receiver is integrated in the interior mirror. E60, E61, E63, E70, E90, E91, E92 The remote control receiver is integrated into the aerial amplifier. The remote control (FBD) receiver picks up radio signals from the ID transmitter and forwards them to the CAS control unit. The Comfort Access control unit (CA control unit) activates the FBD receiver.
5. CAS control unit The CAS control unit (CAS: Car Access System) is the master control unit for all Comfort Access functions. The CAS control unit is the interface to the START/STOP button and to the slot for the ID transmitter. The electronic steering lock is also activated by the CAS control unit. The CAS control unit is connected with the following components via the K-bus (sub-bus): Outside door handle electronics (number depends on model concerned) Comfort Access control unit (CA control unit) Electronic steering lock When the vehicle is idle, communication may take place on the K-bus without waking up the vehicle.
6. START/STOP button The START/STOP button can be used to switch the terminals in sequence (0, R, 15, R, 0). The engine can be started by depressing the clutch or the brake (manual transmission/automatic transmission) and pressing the START-STOP button.
7. Slot for the ID transmitter/remote control On vehicles without Comfort Access: In order to start the engine, the remote control must be latched in place in the slot. On vehicles with Comfort Access: The remote control must be inserted into the slot if the battery in the ID transmitter is discharged. The engine can then be started up. Inserting the ID transmitter into the slot deactivates Comfort Access.
8. JBE: Junction box electronics E70, E81, E87, E90, E91, E92, E93 The junction box electronics activates the central locking system. If the CAS control unit approves the unlocking of the vehicle, for example, the doors will be unlocked.
9. KGM and KBM: Body gateway module and body basic module E60, E61, E63, E64 The body gateway module actuates the central locking in the front doors. The body basic module controls the central locking in the rear doors. If the CAS control unit approves the unlocking of the vehicle, for example, the doors will be unlocked.
10. Comfort Access control unit The Comfort Access control unit (CA control unit) actuates the internal and exterior aerials. An ID transmitter scan is carried out. At the same time, the FBD receiver is activated for any ID transmitters which may respond.

System functions

Comfort Access is used to implement the following functions

1. Passive Entry via driver's door or front passenger door
2. Passive Entry via tailgate
3. Passive Go
4. Passive Exit
5. Disabling an ID transmitter located inside the vehicle
6. Disabling an opposing command
7. Tamperproof lock

Passive Entry via doors

The vehicle is unlocked when the outside door handle is gripped or pulled. Condition: The ID transmitter must be located no further than 1.5 m from the aerial in the outside door handle.

Ideally, the user should carry the ID transmitter in a pocket.

First, the user is authenticated (= authenticity check).

The data transferred during the authenticity check is of course encrypted.

If the ID transmitter authenticity check is successful, the user will be granted access to the vehicle. The central locking is unlocked. The door can be opened.

The same principle is applied for the authenticity check for Passive Entry and Passive Go.

Authenticity check using the example of Passive Entry

1. Trigger signal at outside door handle electronics via capacitive sensor 1.
2. Request sent to outside door handle electronics to locate an ID transmitter via the aerials in the outside door handle. All ID transmitters associated with the vehicle and located outside of it are included in the search (low-frequency radio signal at 125 kHz). The search determines whether an ID transmitter associated with the vehicle is located in the operating range of the aerials in the outside door handle.
3. At the same time, the outside door handle electronics send a message to the CAS control unit via the sub bus (K-bus).
4. All ID transmitters located register with the CAS control unit by sending a radio signal via the FBD receiver (high-frequency radio signal, country-specific, e.g. 868 MHz).
5. The CAS control unit decides which of the registered ID transmitters will be used for the subsequent authenticity check.
6. This selection is sent to the outside door handle electronics in a message via the K-bus. At the same time, a request is sent to the outside door handle electronics to carry out a selective scan of the ID transmitter concerned.
7. All ID transmitters not picked up in this scan end reception readiness for the communication operation currently in progress.
8. The ID transmitter picked up via the selective scan responds by sending a radio signal to the CAS control unit via the FBD receiver (high-frequency radio signal at 868 MHz).
9. The CAS control unit evaluates the response signal and, if confirmation is valid, authorizes Passive Entry. The vehicle is unlocked. In order that the vehicle can be opened quickly, the door lock is mechanically pretensioned with a spring. The spring ensures that the door unlocks whenever the user pulls the outside door handle to its full extent.
10. The tension sensor is set up with redundancy to the capacitive sensor (e.g. capacitive sensor 1 deactivated due to long-term lack of use). When the tension sensor detects the "Outside door handle pulled" signal, the door is unlocked. The door can be opened by pulling on the outside door handle again.

Passive Entry via the tailgate or front rear window

Comfort Access can be used to open the tailgate without actively using the ID transmitter. Condition: The ID transmitter must be located no further than 1.5 m from the aerial. Ideally, the user should carry the ID transmitter in a pocket.

To open the tailgate, it is necessary to press and hold the tailgate button for approximately 500 ms (top half of BMW logo on the E81, E87, grip on all other vehicles). If an ID transmitter is located in the vicinity of the luggage compartment, the tailgate will open.

If an ID transmitter is located inside the luggage compartment when the tailgate is closed (and there are no authorized ID sensors outside the vehicle), the tailgate will open up again.

The user's attention is drawn to the anti-theft alarm as follows

1. Visual signal via turn signal lights
2. Acoustic signal via siren, US version only

1. E61, E91: rear window

To open the rear window, the rear window button must be pressed for approx. 500 ms (under the rear window wiper arm).

If an ID transmitter is located in the vicinity of the rear of the vehicle, the rear window will open.

If an ID transmitter is located inside the luggage compartment when the rear window is closed (and there are no authorized ID sensors outside the vehicle), the rear window will open again.

The user's attention is drawn to this as follows: Visual signal via indicators and acoustic signal via sirens (on anti-theft alarm system).

Passive Go

In order to switch the terminal and/or start up the engine, the ID transmitter must simply be located inside the vehicle ( not necessarily in the slot).

On the following models, the luggage compartment counts as part of the interior: E61, E70, E81, E87, E91.

On all other models, it is not possible to start the engine if an ID transmitter is detected in the luggage compartment.

In principle, the authenticity check required is the same as that for Passive Entry (except that it is run via the interior aerials).

If there are no ID transmitters inside the vehicle when the START-STOP button is pressed: Check-Control message on instrument cluster.

Press the START/STOP button to switch the terminals. The terminal switching sequence is as follows: 0 -> terminal R -> terminal 15 -> terminal R -> 0.

The START/STOP button must be pressed for approximately 500 ms in order to start up the engine. The clutch pedal or brake pedal (manual transmission or automatic transmission respectively) must be depressed at the same time.

The engine may be started up in any terminal position.

Once the engine has been switched off, it may be restarted within 5 seconds even if no ID transmitter is detected inside the vehicle (i.e. no valid drive authorization). This safety measure is required for possible emergencies.

Passive Exit

The sensitive area on the outside door handle must be touched (depends on model concerned) for the vehicle to be locked and then secured. Your hand must touch the middle of the sensitive area for at least 1 second.

If the locking area is touched for approx. 3 seconds, auto-remote closing will start. The side windows and sliding/tilting sunroof or Panorama glass sunroof on the E61/E91 then close. On the E64, the convertible top closes. If applicable, the exterior mirrors are folded in.

Auto-remote opening via the outside door handle is not possible.

Terminal R is deactivated when the outside door handle is locked.

Terminal 15 is not deactivated when the vehicle is locked. A Check-Control message appears as a warning when the driver's door is opened with terminal 15 ON.

Special feature: Comfort Access allows the vehicle to be locked whilst the engine is running.

1. E93

Note. No convenience closing of the hardtop via the exterior door handle electronics.

It is not possible to close the hardtop via the exterior door handle electronics. Convenience closing is performed at the lock cylinder.

Disabling an ID transmitter located inside the vehicle

When the vehicle is closed via the outside door handle, any ID transmitter inside the vehicle will be detected.

This ID transmitter is disabled for all Comfort Access functions. However, it is still possible to access the luggage compartment. The ID transmitter is reactivated when the vehicle is unlocked again.

Disabling an opposing command

When the vehicle is unlocked via the outside door handle, it cannot be locked again for approx. 2 seconds.

Similarly, when the vehicle is locked via the outside door handle, it cannot be unlocked again for approximately 2 seconds.

This allows the user to pull on the outside door handle to check that the vehicle is actually locked.

Tamperproof lock

The vehicle may only be locked and unlocked consecutively a maximum of 8 times. After this, the tamperproof lock is activated.

Operation is disabled for 10 seconds. The tamperproof lock is deactivated completely after 5 minutes. Once again, the vehicle may then only be locked and unlocked consecutively a maximum of 8 times.

National versions

The following details are available with regard to national versions

1. E93

Convenience functions performed using the remote control or ID transmitter depend on the national version concerned.

Conditions for operating Comfort Access (option 322) with the remote control or ID transmitter

COMFORT ACCESS CHART

Scheme 31

Park Distance Control (PDC) is an item of special equipment. Park Distance Control (i.e.: parking aid) assists the driver when he is parking and maneuvering in tight spaces. This means that even small parking spaces can be used. At the same time, parking damage is reduced.

PDC uses ultrasonic sensors to measure the distance to objects within the effective range.

PDC is available in the following versions

1. Option 507: Park Distance Control (PDC), rear
2. Option 508: Park Distance Control (PDC), front and rear

The PDC button in the center console switch cluster is only provided with option 508.

Compared to earlier systems, PDC has the following new features

1. Modified ultrasonic sensor with decoupling element on sensor housing
2. Increased range for ultrasonic sensor: 2.5 meters front and rear
3. Good detection of obstacles while remaining insensitive to echo pulses from the ground

The driver is warned of an object that could cause a collision as follows

1. Acoustic warning via (depends on equipment fitted): E70 Mid-range loudspeakers with Multimedia Platform (CHAMP), Multi-audio system controller (M-ASK) or Car Communication Computer (CCC) E87, E90, E91, E92, E93 2 acoustic generators (1 front, 1 rear) with radio without audio system Mid-range loudspeaker with BMW "Professional" radio, multi-audio system controller or Car Communication Computer R56 1 acoustic generators (rear) with Radio Wave Mid-range loudspeaker with Radio Wave CD, Radio Boost CD or Car Communication Computer
2. Visual warning by PDC image with multi-audio system controller and Car Communication Computer

The visual warning function in particular enables PDC to provide assistance for drivers who are hard of hearing or have restricted mobility.

The visual warning has additional benefits if the noise level inside the vehicle is very high (e.g. loud music).

PDC is not a substitute for the driver's personal judgement with respect to obstacles.

The ultrasonic sensors also have a "blind spot". In this blind spot, objects can no longer be detected.

The detection of objects can test the physical limits of ultrasonic measurements if the ultrasonic waves are reflected either poorly or not at all (e.g. due to trailer tow bars or narrow objects).

Objects close to the ground can suddenly "disappear", before a continuous tone sounds (e.g. a high curbstone).

Loud noises outside and inside the vehicle can drown out the PDC signal tone.

It therefore remains the driver's responsibility to watch for obstacles, even in vehicles with PDC.

PDC consists of the following components

1. Ultrasonic sensors E70 8 ultrasonic sensors with option 508: Park Distance Control (PDC), front and rear E87, E90, E91, E92, E93 4 ultrasonic sensors with option 507: Park Distance Control (PDC), rear 8 ultrasonic sensors with option 508: Park Distance Control (PDC), front and rear R56 4 ultrasonic sensors with option 507: Park Distance Control (PDC), rear There are 4 ultrasonic sensors in each of the front and rear bumpers. The ultrasonic sensors emit ultrasonic pulses. These ultrasonic pulses are reflected by obstacles (echo pulses). The ultrasonic sensors receive and amplify these echo pulses. The amplified echo pulses are then converted into a digital signal. Each ultrasonic sensor has its own electronics, its own power supply and its own data connection to the PDC control unit.

The measuring range of the ultrasonic sensors is between approx. 25 centimeters and a maximum of approx. 250 centimeters. A continuous warning tone sounds when the distance is less than about 25 centimeters.

Dirty sensors, moisture, ice and snow can also cause the continuous warning tone to sound.

Note. Cleaning the ultrasonic sensors

To make sure the system remains fully operational, keep the ultrasonic sensors clean and free from ice. Do not clean by spraying high-pressure washers directly at the ultrasonic sensors. When cleaning, always maintain a minimum distance of at least 10 centimeters.

Note. Make sure the decoupling element on ultrasonic sensor is correctly located.

The respective decoupling element must be correctly located. Otherwise, transmission and reception will be impaired.

1. PDC button E70, E87, E90, E91, E92, E93 The PDC button is integrated in the center console switch cluster (no control unit). The signal from the PDC button is read by the IHKA (or IHKR/IHR control unit) control unit. In turn, the IHKA control unit sends a signal on the K-CAN. The PDC button is used to manually switch the Park Distance Control system on and off. When the PDC is switched on, the function LED in the PDC button lights up. If a fault develops in the PDC, the function LED in the PDC button flashes.
2. PDC control unit The PDC control unit controls the ultrasonic sensors for transmitting ultrasonic pulses. The PDC control unit also receives the digital signals from the individual ultrasonic sensors. From the individual digital signals, the PDC control unit calculates the minimum distance between the ultrasonic sensor and the object. When an object is detected, an acoustic warning and a visual warning are given.

The PDC control unit is connected to various other control units via the bus system

1. RAD2, CHAMP, M-ASK or CCC: BMW "Professional" radio, Multimedia Platform, multi-audio system controller or Car Communication Computer E70, E87, E90, E91, E92, E93 Depending on the equipment fitted, the audio master emits acoustic PDC warnings via the mid-range loudspeaker.
2. Radio Wave CD, Radio Boost CD or CCC: Radio Wave CD, Radio Boost CD or Car Communication Computer R56 Depending on the equipment fitted, the audio master emits acoustic PDC warnings via the mid-range loudspeaker.
3. CID: Central Information Display E70, E87, E90, E91, E92, E93 The visual PDC warnings are given in the Central Information Display (CID). In addition, information regarding a Check-Control message that may be present is shown.
4. KOMBI: Instrument cluster E70, E87, E90, E91, E92, E93 A current Check-Control message is indicated by a symbol in the LCD display in the instrument cluster. Moreover, the instrument cluster also provides the exterior temperature and the kilometer reading for the PDC control unit. The PDC control unit is then able to correct the calculated distance with a factor corresponding to the outside temperature.
5. KOMBI and CID: Instrument cluster and Central Information Display R56 The instrument cluster has two section. The instrument cluster itself is in the middle of the dashboard. The auxiliary instrument is on the steering column. The KOMBI and the CID are both control units. These control units are plugged into one another an installed together in the dashboard. All equipment versions are connected to the auxiliary instrument via a K-bus. The auxiliary instrument is the gateway to the K-CAN. A current Check-Control message is indicated by a symbol in the LCD display in the auxiliary instrument. The instrument cluster provides the exterior temperature and the kilometer reading for the PDC control unit. The PDC control unit is then able to correct the calculated distance with a factor corresponding to the outside temperature.
6. EGS: Electronic transmission control On vehicles with automatic transmission, the electronic transmission control (ESG) supplies the signal that reverse gear is engaged. The PDC control unit activates PDC after a short delay (approx. 1 second). This prevents PDC from being unexpectedly activated on vehicles with automatic transmission, fro example when the selector lever is moved from "P" to "N" via "R".
7. DSC: Dynamic Stability Control The DSC control unit supplies the PDC with information about the road speed and distance travelled.
8. FRM: Footwell module On vehicles with manual transmission, the footwell module (FRM) supplies the signal that reverse gear is engaged.
9. CAS: Car access system The CAS control unit supplies the PDC with the terminal status (e.g. terminal 15).
10. AHM: Trailer module The trailer module (AHM) sends a signal indicating whether the vehicle is towing a trailer or if a rear carrier rack is fitted. If a trailer or rear carrier rack is recognized, the acoustic and visual warnings for the rear bumper are deactivated.

PDC incorporates the following functions

1. Acoustic warnings
2. Visual warning with multi-audio system controller and Car Communication Computer
3. Check Control
4. System limits

Acoustic warnings

The acoustic warnings are emitted by

1. E70 Mid-range loudspeaker with CHAMP, M-ASK or CCC If an object is detected by 2 ultrasonic sensors, the loudspeaker closest to the object is actuated. The mid-range loudspeakers can be actuated. (depending on the model concerned, the mid-range loudspeakers in the left/right front doors or left/right rear doors are actuated, for example) If an object is detected by the central ultrasonic sensors, the mid-range loudspeakers on the left and right-hand sides are actuated together.
2. E87, E90, E91, E92, E93 2 acoustic generators (1 front, 1 rear) with radio without audio system The PDC control unit directly actuates the acoustic generators (front/rear in vehicle interior). Within the acoustic generator, the control signal is transformed to approx. 48 volts. This voltage excites a piezoceramic element that together with the resonator (housing) generates a warning tone. Up to 09/2006, the tone is in the frequency range of approximately 1 kHz. From 09/2006 the tone is in the frequency range of approximately 1.5 kHz (front) or 1.0 kHz (rear). Mid-range loudspeaker with RAD 2, M-ASK or CCC If an object is detected by 2 ultrasonic sensors, the loudspeaker closest to the object is actuated. The mid-range loudspeakers can be actuated. (e.g. the mid-range loudspeakers in the front doors, left/right, in the rear shelf, left/right, in the rear doors, left/right, in the rear shelf, left/right or in the rear side trim, left/right are actuated, depending on the vehicle model.) If an object is detected by the central ultrasonic sensors, the mid-range loudspeakers on the left and right-hand sides are actuated together.
3. R56 1 acoustic generator (rear) with Radio Wave The PDC control unit directly actuates the acoustic generators (in rear of vehicle interior). Within the acoustic generator, the control signal is transformed to approx. 48 volts. This voltage excites a piezoceramic element that together with the resonator (housing) generates a warning tone. The tone is in the frequency range of approximately 1 kHz. Mid-range loudspeakers with Radio Wave CD, Radio Boost CD or CCC If an object is detected by 2 ultrasonic sensors, the loudspeaker closest to the object is actuated. The midrange loudspeaker on the left/right can be actuated. If an object is detected by the central ultrasonic sensors, the mid-range loudspeakers on the left and right-hand sides are actuated together.

The distance to the object determines the tone sequence for the acoustic warning (the smaller the distance, the faster the tone sequence).

A distance of less than approx. 25 centimeters is indicated by a continuous tone. The continuous tone is emitted alternately from the front and the rear.

If the vehicle moves away from the object, the warning tone will be cancelled when the distance increases by more than 10 centimeters.

Effective range for acoustic warnings

1. approx. 60 centimeters for the ultrasonic sensors at the two corners of the front bumper
2. approx. 70 centimeters for the two middle ultrasonic sensors in the front bumper
3. approx. 60 centimeters for the ultrasonic sensors at the two corners of the rear bumper
4. approx. 150 centimeters for the two middle ultrasonic sensors in the rear bumper

Optical warning with multimedia platform or multi audio system controller or Car Communication Computer

The visual PDC warnings are given in the Central Information Display (CID). This is subject to the PDC display in the CID being active.

The visual warnings are given earlier than the acoustic warnings.

The effective range is approx. 2.5 meters at the front and rear.

The graphic display is shown on the CID. The PDC control unit supplies the distance between the ultrasonic sensor and the object detected via the K-CAN.

The PDC display on the CID is an overhead view of the vehicle with the effective range of the ultrasonic sensors.

The distance to objects detected is shown in the colors of traffic lights

1. Distance between 200 (250) and 101 centimeters: green
2. Distance between 100 an 51 centimeters: yellow
3. Distance less than 50 centimeters: Red

The PDC display appears as soon as the PDC is switched on (manually or automatically). The PDC display overrides other displays in the CID. When the PDC is switched off again, the previous display automatically appears again in the Central Information Display.

Check Control

If a fault should develop in the PDC, the function LED in the PDC button will flash with a frequency of 2 Hz.

In this situation, PDC cannot be switched on.

At the same time, a Check-Control message is displayed in the following form

1. Symbol in the LCD display in the instrument cluster
2. The following text appears in the status line of the Central Information Display: "PDC failure!" In the menu "BMW Service", the following text can be called up in the submenu "Check-Control messages": "Park Distance Control No acoustic warning available for Park Distance Control PDC. Have the problem checked by BMW Service as soon as possible."

If a fault memory entry is recorded, the kilometer reading and the outside temperature are recorded along with the type of fault.

System limits

PDC is not a substitute for the driver's personal judgement with respect to obstacles.

The ultrasonic sensors also have a "blind spot". In this blind spot, objects can no longer be detected.

The detection of objects can test the physical limits of ultrasonic measurements if the ultrasonic waves are reflected either poorly or not at all (e.g. due to trailer tow bars or narrow objects).

Objects close to the ground can suddenly "disappear", before a continuous tone sounds (e.g. a high curbstone).

Loud noises outside and inside the vehicle can drown out the PDC signal tone.

It therefore remains the driver's responsibility to watch for obstacles, even in vehicles with PDC.

During operation, the following system functions, which require explanation, can occur due to the limits of the functional range (for the driver)

1. Under the following conditions, it could happen that the PDC gives a warning, even though there is no obstacle within the effective range: Ultrasonic sensor incorrectly located in its bracket Heavy rainfall Ultrasonic sensors covered in snow Exhaust gases Echo pulses caused by ground, e.g. extremely coarse road surface or high grass Very smooth walls in large, enclosed, rectangular spaces, e.g. in underground car parks (interference from previously reflected echo pulses) Protective cap for trailer coupling ball head incorrectly seated or objects being transported protruding into the effective range of the ultrasonic sensors.
2. Under the following conditions, the PDC may not recognize an obstacle that is present: Objects close to the ground (no reflection) Objects with corners and sharp edges (no reflection) If you drive alongside a wall for more than 3 seconds, the acoustic warning will be deactivated. Here, the distance must be greater than the effective range for the continuous tone (approx. 25 centimeters). As soon as the distance drops below 25 centimeters, the continuous tone will sound again. If the vehicle approaches an object too fast Starting up and moving away too quickly while PDC is starting

Conditions for switching on and off

PDC is switched on under the following conditions

1. PDC button pressed (PDC switched on manually), option 508 only
2. Reverse gear engaged (PDC switched on automatically)

PDC is switched off under the following conditions

1. Reverse gear disengaged, option 507 only
2. PDC button pressed (PDC switched off manually), option 508 only
3. Ignition switched off (PDC switched off automatically
4. After driving approx. 50 meters
5. After exceeding a speed of 30 km/h

When towing a trailer or driving with a rear carrier rack, the acoustic and visual warnings for the rear bumper are deactivated by the trailer module (AHM).

The trailer or rear carrier rack must be electrically connected.

Operation

The visual warning (PDC display) is switched on in the Central Information Display (CID) as follows

1. "Settings (i)" menu
2. "Vehicle settings" menu
3. "PDC" menu
4. Activate "Display on"

Scheme 32

The following cruise controls are available at the start of series production of the E90 (12/2004)

1. Option 540 "Cruise control" The set speed is maintained via the engine. (Set speed = stored desired speed) Accelerating to the set speed: Engine intervention via the DME/DDE (DME = "digital engine electronics"; DDE = "digital diesel electronics") Decelerating to the set speed: Via the engine drag-torque
2. Option 541 "Active Cruise Control" With Active Cruise Control, a timed separation is maintained from the vehicle ahead. The separation can be adjusted. Accelerating to the set speed: Engine intervention via the DME/DDE Decelerating to the set speed: Brake intervention via the DSC (Dynamic Stability Control)
3. Option 544 "Cruise control with brake function" The set speed is maintained via engine and brake intervention. Accelerating to the set speed: Engine intervention via the DME/DDE Decelerating to the set speed: Brake intervention via the DSC

Cruise control is a comfort system. Adjustments by the driver will always have a higher priority (= importance) than cruise control.

The driver should decide whether (and how) the system is used based on road and traffic conditions and visibility.

With the start of series production of the E90, longitudinal dynamics management (LDM) will also be introduced. Longitudinal dynamics management consists of various function blocks (e.g.: Cruise control with brake function or Active Cruise Control option). These function blocks are grouped together into a control unit by the corresponding software. The control unit is called the LDM control unit.

The LDM control unit evaluates all relevant data for cruise control. (e.g.: The ACC sensor sends the information "Vehicle monitored". This information is evaluated in the LDM control unit).

1. E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit.

In this SI Technology (SBT) bulletin, only longitudinal dynamic management and thus the Cruise control with brake function or Active Cruise Control option is described.

Longitudinal dynamics management is available in connection with the following option (special equipment)

1. Option 541 "Active Cruise Control" or
2. Option 544 "Cruise control with brake function" E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit.

Option 541 "Active Cruise Control"

The 2nd generation Active Cruise Control option will be used for the first time with the E63/E64 from 09/2004.

Active Cruise Control is a comfortable spacing and cruise control.

The distance from the vehicle ahead can be selected from 4 fixed timed separations. (EURO version: 1.0 - 1.5 - 2.0 - 2.5 seconds)

This means that the as speed changes, so does the distance to the vehicle ahead.

The legally prescribed minimum distance is not undershot when control is active.

Differences between option "Active Cruise Control" on E90, E91, E92, E93 and option "Active Cruise Control" on E60, E61, E63, E64, E65, E66

1. On the E90, E91, E92 (including all-wheel drive) and E93, the data for the longitudinal dynamic management are evaluated in the LDM control unit.
2. On the E60, E61, E63, E64, E65, E66, the data for the longitudinal dynamic management are evaluated in the ACC control unit (i.e.: there is no LDM control unit fitted).

Option 544 "Cruise control with brake function"

Differences between "cruise control with brake function" and "cruise control"

1. Constant roadspeed, even downhill: The set speed is also maintained when going downhill. (Brake intervention via the DSC)
2. The lateral acceleration in bends is restricted to a comfortable level.
3. Indicator disc in the instrument cluster: The indicator disc shows the set speed.
4. Brief display in the LCD display of the instrument cluster: The newly selected set speed is shown briefly in the LCD display.

The following components send signals for the cruise control

1. Cruise-control system steering-column stalk Cruise control is set and called up using the cruise control system steering-column stalk.
2. ACC sensor The ACC sensor monitors the distance, angle and relative speed of vehicles driving ahead. (Relative speed: The relative speed is the speed difference between the two moving objects, that is, the speed difference of the two objects relative to each other.) The ACC sensor is a radar sensor. The ACC sensor has a limited monitoring range (approx. 120 meters).
3. LDM control unit The LDM control unit is the interface to the engine and to the brakes. In the LDM control unit, the driver's entries regarding the cruise control system are monitored and evaluated. The "cruise control with brake function" option is integrated in the LDM control unit. E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit. If Active Cruise Control is fitted, the LDM control unit evaluates the data sent from the ACC sensor.

The LDM also communicates with the following control units

1. Instrument cluster The instrument cluster shows all displays for cruise control. An indicator disc in the round instrument shows the set speed. The LCD display briefly shows the newly selected set speed (approximately 6 seconds). In addition, the LCD display also shows a Check-Control message. With Active Cruise Control, there are also the following displays: Monitored vehicle (Display through lit icon in the instrument cluster) Request for action to driver (Display through flashing icon in the instrument cluster. Depending on the national version, an acoustic warning is also made.) Selected distance from vehicle driving ahead (Display via icon in the instrument cluster)
2. DSC: Dynamic Stability Control The current status of the vehicle is detected by the DSC, e.g. by evaluating the following sensor signals: Rate of yaw (measure of movement of the car about its vertical axis) Steering angle Information on the brake pressure Circumferential wheel speed The DSC then transmits data about the current vehicle status to the LDM. The following data is transmitted by the LDM to the DSC: Request for vehicle deceleration The request for vehicle deceleration from the LDM is received by the DSC via the PT-CAN. DSC reduces the speed. To do this, DSC intervenes in the brake system. (goal: comfortable vehicle deceleration. No DSC intervention in the sense of enhanced operating stability.) E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit. With automatic braking, the brake lights are activated depending on vehicle deceleration (legally prescribed).
3. DME or DDE: Digital engine electronics or digital diesel electronics The DME/DDE controls the engine intervention. The following data is transmitted by the LDM to the DME or DDE: Current torque request The following data is transmitted to the LDM from the DME or the DDE: Driver's command (signals from accelerator pedal module) E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit.
4. JBE: Junction box electronics The JBE is the data interface (= gateway) between the K-CAN and the PT-CAN. (K-CAN = body CAN; PT-CAN = powertrain CAN.) Signals from the F-CAN (Chassis CAN) are simply looped through. (No signal processing in the JBE. The F-CAN cables are simply routed through the junction box housing.) The junction box consists of the junction box electronics and the electrical distribution center. The diagnosis cable is connected to the junction-box electronics.
5. FPM: Accelerator pedal module The accelerator pedal module signals the driver's command. This signal is required to check the respective driving status. (evaluation via DME/DDE) By pressing the accelerator pedal, the specified speed of the cruise control can be overridden at any time.
6. Brake light switch The brake light switch tells the cruise control system when the brake pedal has been pressed. Cruise control is deactivated if braking actions are necessary.
7. Clutch mode (manual transmission only) Clutch engagement/disengagement is recognized by the signal from the clutch module. During the clutch engagement/disengagement process, the engine speed is maintained at an optimal speed range by the DME or DDE. After the clutch has been reengaged, the DME/DDE will adjust back to the current torque request from the Active Cruise Control. If the engine speed is too high or too low, an audible signal and a Check-Control message prompt the driver to change gear. The prompt to upshift when the engine speed is too high is only made during the warm-up phase of the engine.

Active Cruise Control has a variant encoding which is coordinated with the differential ratio. If a different rear differential unit is installed, it may be the case that Active Cruise Control will deactivate itself in manual transmissions, particularly in the higher gears. In this case, no fault is entered in the fault memory.

1. EGS: Electronic transmission control The evaluated cruise control data is sent from the LDM control unit to the DME or DDE. The EGS evaluates the data from the DME or DDE. The adaptive transmission control (constituent component of electronic transmission control) adapts the shift characteristics of the driving programme to the driver's commands and the driving situation.
2. SZL: Steering column switch cluster The SZL processes all data from the cruise-control system steering-column stalk. The evaluated switch signals are sent by the SZL through the F-CAN to the LDM control unit. Signal path: Cruise control system steering-column stalk -> SZL -> F-CAN -> DSC control unit (acts as a gateway) -> PT-CAN -> LDM control unit E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit.
3. FRM: Footwell module When cruise control is in operation, the brake lights are actuated during automatic braking (legal requirement). To this end, a signal must be sent from the DSC to the footwell module via the PT-CAN. The option "Active Cruise Control" uses the "turn signals" signal from the footwell module for assistance when changing lanes. In other words, if a left turn signal is given before overtaking, the distance to the vehicle in front is reduced. The vehicle to be overtaken is "ignored" more easily. Conversely, in the event of a change to the right-hand lane, a vehicle driving there is registered more quickly. With the vehicle's own calculated expected lane, the sideways deviation of each monitored object can be determined for the vehicle's own lane.
4. M-ASK or CCC and CID: Multi-audio system controller/Car Communication Computer and Central Information Display For the instrument cluster, the M-ASK or CCC serves as the interface to the CID. Amongst other things, the CID displays detailed information about the Check-Control messages. To back up the Check-Control message, the MASK /CCC emit audible warnings through the loudspeakers (depending on national version). The instrument cluster controls these warnings by means of the K-CAN.

The system functions of "cruise control with brake function" and "Active Cruise Control" are described below.

Option "Cruise control with brake function"

1. Cruise control Cruise control has the following subfunctions: Cruise control system Limited lateral acceleration when cornering (up to max. 4.0 m/s2) Depending on the driving situation, the LDM control unit reports to the DME or DDE or the DSC as follows: DME or DDE: Accelerate DSC: Brake E92 from 06/2006 and E90, E91 from 09/2006 and E93 from 12/2006 The LDM control unit is no longer fitted on vehicles with option 544 "Cruise control with brake function". Because of a software modification in the DSC control unit (DSC Mk60E5), the DSC control unit assumes control of the functions of the LDM control unit.

Option "Active Cruise Control"

1. Monitor object ahead
2. Cruise control
3. Lens heating
4. Low-voltage cutout and high-voltage protection for ACC sensor
5. Self-diagnosis and compensation for minor horizontal adjustments
6. System limits

Monitor object ahead

Objects are all vehicles in the same lane. The vehicles on other lanes are of no interest for Active Cruise Control.

In the same lane, the vehicle immediately ahead is selected as the object.

With the calculated expected same lane, the lateral deviation of each monitored object to the same lane can be determined.

The radar waves received cannot distinguish between animals, vehicles and traffic signs. In order to prevent incorrect reactions, stationary objects and traffic in the other direction are ignored in the distance control.

Active Cruise Control differentiates between 2 driving conditions

1. Cruise control with specified set speed A selected set speed (in the range 30 km/h - 180 km/h) is automatically maintained on open roads without vehicles driving ahead.
2. Cruise control with speed adapted to that of vehicle driving ahead If a slower vehicle is detected on the vehicle's own track, the vehicle's own speed will be adapted to that of the vehicle driving ahead At the same time, a distance from this vehicle preset by the driver is established (4 fixed timed separations can be selected). The timed separation from a vehicle driving ahead is no less than 1 second under stationary conditions. In certain conditions (e.g. when a vehicle cuts in a short distance ahead), this timed separation may briefly be less than 1 second.

Lens heating

The lens of the ACC sensor is made of plastic. The built-in lens heating ensures better availability of Active Cruise Control in winter weather conditions.

The lens heating is activated by the ACC sensor. The heating is controlled via a pulse-width modulated signal (PWM signal). The heating coil is integrated into the lens of the ACC sensor

The lens heating is only activated within a certain ambient temperature range (approx. +5 °C to -5 °C). Reason: Only at temperatures around zero is snow wet or moist. At temperatures well below this, snow will be dry. To prevent snow from thawing on the lens and creating an artificial coating, the heating is switched off below a certain ambient temperature. The current ambient temperature value is transmitted by the instrument cluster.

1. Conditions required for switch-on Engine ON ACC ON Ambient temperature between -5 °C and +5°C
2. Safety cutout Temperature in ACC sensor over 50 °C (measured by interior temperature sensor in ACC sensor control unit) Voltage greater than 16 volts The safety cutout shuts down the lens heating. Active Cruise Control remains activated. (No fault memory entry)
3. Monitoring The lens heating is monitored for open and short circuits in the heating coil. If the monitoring reports a fault, Active Cruise Control will be shut down. (Fault memory entry)

Low-voltage cutout and high-voltage protection for ACC sensor

The ACC sensor works with a supply voltage of 9 to 16 volts.

1. Low-voltage cutout If the on-board supply voltage drops below about 9 volts, the ACC sensor will perform a low-voltage cutout and a fault memory entry will be stored. The ACC sensor will be reactivated when the on-board supply voltage exceeds 9.8 volts again.
2. Overvoltage protection If the on-board supply voltage exceeds about 17.5 volts, the ACC sensor will perform a cutout with a fault memory entry. The ACC sensor will be reactivated when the on-board supply voltage drops below 17.0 volts again.

Self-diagnosis and compensation for minor horizontal adjustments

External forces may change the alignment of the ACC sensor. A horizontal change leads to function limitations. (Function limitations encountered are, e.g.: reaction to vehicles in the next lane or late reaction to vehicles in the same lane).

Self-diagnosis allows the ACC sensor to compensate for minor horizontal adjustments of up to 1°.

If a horizontal adjustment of more than 1° is detected, Active Cruise Control will be deactivated and a fault will be stored in the fault memory. A Check-Control message will be issued.

If the limit of the functional range is reached, the driver is prompted to act (brake or swerve) as follows: Display for the monitored vehicle flashes red and an acoustic signal sounds.

During operation, the following system functions, which require explanation, can occur due to the limits of the functional range (for the driver)

1. Limited range and deceleration The range of the ACC sensor is limited (approximately 120 meters). Rain, snow and fog absorb radar waves. This will significantly reduce the range of the ACC sensor. Active Cruise Control is only able to effect limited deceleration via the DSC (a maximum of 2.5 m/s2) This means that cruise control is only able to compensate for a limited relative speed. Active Cruise Control operation is only possible in flowing traffic in a road speed range from 30 km/h to 180 km/h.
2. Lateral monitoring range The lateral monitoring range of the ACC sensor is limited, meaning that a monitored vehicle ahead could be lost due to a tight bend. In such cases, cruise control will not accelerate to the set speed for approximately 2 seconds. This will prevent the vehicle from accelerating too close to the vehicle ahead, which is possibly only briefly not being monitored. When driving straight ahead, this can cause a delayed reaction to another vehicle cutting in close in front. The vehicle cutting in will not be monitored by the cruise control until it is clearly in the same lane as the vehicle with Active Cruise Control.
3. Display for monitored vehicle does not light up, the vehicle remains below the set speed and does not accelerate further Causes: On sharp bends, the vehicle's speed will be controlled in such a way that lateral acceleration does not exceed a maximum of 4.0 m/s2 to maintain driving comfort.
4. Timed separation less than 1 second The timed separation from a vehicle driving ahead is no less than 1 second when cruise control is active. In certain conditions (e.g. when a vehicle cuts in a short distance ahead), this timed separation may briefly be less than 1 second. If the deceleration induced by the cruise control is not sufficient, the driver will have to intervene directly.
5. ACC sensor blind If the ACC sensor is blinded, Active Cruise Control shuts down. (Blinding, e.g. due to extremely heavy snowfall, through a layer of ice on the sensor or through dirt) Cruise control can be reactivated after the ACC sensor has been cleaned.
6. Bends cannot be detected in an anticipatory manner Active Cruise Control is unable to work in an anticipatory manner when the vehicle is cornering. It is only able to react to existing lateral acceleration when it is already on the bend. For this reason, the driver is responsible for ensuring that an appropriate speed is being driven as the vehicle enters the bend.
7. Active Cruise Control deactivated after DSC intervention or brake application by the driver Cruise control will be deactivated following DSC intervention or a brake application by the driver. (DSC intervention in the sense of enhanced operating stability.) Cruise control will then have to be reactivated at the cruise control system steering-column stalk.

US and CDN national versions

Different timed separations encoded for following mode (1.5 - 1.8 - 2.2 - 2.5 seconds)

US and GB national versions

The option "Active Cruise Control" is effective in the speed range 20 mph to 110 mph.

Speed can be selected in steps of 1 mph and 5 mph.

Subject to change.