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Car Access System



Car Access System

The new MINI (R56) is equipped with a Car Access System (CAS). The CAS is derived from the BMW 1 Series and 3 Series. The MINI also assumes a leading position in its vehicle class in the area of comfort (UKL1+).

The Car Access System (CAS) regulates the access options to the vehicle. The CAS control module is the master control module, e.g. for the following systems.
- Electronic vehicle immobilization
- Central locking
- Comfort Access
- Electric steering interlock
- Power windows

This means the MINI now also has a mount for the remote control and a START-STOP unit with START-STOP button.

The electronic immobilizer is an enhancement (4th generation).

Brief description of components
The following components for the Car Access System are described:

CAS control module
The CAS control module is the master control module for the above-mentioned systems. The CAS control module is the interface to the START-STOP unit with a fixture for the remote control. The electrical steering interlock is also activated by the CAS control module. The CAS control module is connected directly to the K-CAN (body CAN). The electrical steering interlock is connected to the CAS via the K bus.







The electronic immobilizer of the 4th generation is integrated in the Car Access System.

The START-STOP unit is connected via a 14-pin plug-in connection to the CAS control module. The START-STOP button is integrated in the START-STOP unit together with the fixture for the remote control.

START-STOP button and fixture for remote control
Together with the remote control, the START-STOP button is used to start the vehicle. The remote control contains an authorization code for each vehicle.







After inserting the remote control in the mounting, the authorization of the transponder is read out. When the CAS detects an authorized remote control, terminal R is switched on. At the same time, the remote control is locked in the fixture. The withdrawal lock is locked by a solenoid switch. The locked remote control is a precondition for switching the terminals (terminal R, terminal 15 with engine on/off).

A withdrawal lock prevents the remote control from being pulled out under the following conditions:
- Engine running
- Speed signal greater than 0 km/h
- With automatic transmission, not in selector-lever position "P" (park)

Pressing the START-STOP button initializes the engine start. Here, the CAS control module checks the following requirements:
- With automatic transmission, selector-lever position "P" or "N" and brake operation
- With manual transmission, clutch operation

When all the requirements have been met, the engine is started by the CAS control module (activation of terminal 50). To stop the engine, press the START-STOP button once again. The engine is stopped; terminal R remains switched on (long press, terminal 30). On vehicles with automatic transmissions, the engine can only be stopped with the vehicle at a standstill when the parking lock is engaged. This fully electronic access to the vehicle has the following advantages:
- Increased reliability of the pin signals due to non-wearing, redundant sensor system
- Defined switching characteristics of the terminal outputs
- Electronic access to the vehicle e.g. for independent heating and for telestart (remote starting of the engine)

NOTE: Emergency function while the vehicle is being driven.

For safety reasons, the engine can be stopped while the vehicle is being driven by pressing the START-STOP button. A renewed start in this case is possible without additional brake operation or clutch operation.

NOTE: Engine start with Comfort Access.

With Comfort Access, the remote control does not have to be in the mounting at engine start-up.

Electric steering interlock
After authentication by the CAS, the electrical steering interlock is supplied with current. Only now can the steering be unlocked or locked. An engine start is only permitted when the electrical steering interlock has been unlocked and secured.







The electrical steering interlock can only be locked when the vehicle is at a standstill and the engine has stopped. If no unlocking procedure or locking procedure is carried out, the electrical steering interlock is secured and without current.

System functions
The following system functions are described for the Car Access System (CAS):
- Terminal control
- Electronic vehicle immobilization
- Comfort start
- Control of the electrical steering interlock
- Remote control of the central-locking system
- Central control of the central locking system
- Central control of the power windows
- Central control from Comfort Access (CA: comfort access)
- Waking the MOST via the K-CAN for a Telematic service
- Central data source for the vehicle order and redundant data storage for vehicle data

Terminal control
The CAS activates the following terminals via the START-STOP unit as follows:
- Terminal R
To maintain the starting capability of the vehicle, the CAS switches terminal R off automatically. After opening and closing the driver's door and with no seat occupation, terminal R is switched off after 8 minutes.
- Terminal 15
The CAS controls terminal 15 (= switched positive power supply) for all electrical systems.
- Wake-up line (terminal 15 wake up)
Switching on terminal 15 activates (wakens) the control modules on the PT-CAN via the wake-up line.
- Terminal 50L
In the starting operation, terminal 50L to the starter motor is switched.
- Switched terminal 30g
Some consumer units (e.g. SHD, DSC) are connected to terminal 30g.
Terminal 30g is switched from the CAS. The consumer unit shutdown at terminal 30g lowers the closed-circuit current.

Electronic immobilizer (petrol engines)
The electronic immobilizer is both an anti-theft device and start release. On the MINI, a newly developed electronic immobilizer (4th generation) is introduced. This development uses a new and modern encryption method. Each vehicle is assigned a 128-bit secret code. This secret code is stored in a BMW database. This means that the secret code is only known to BMW. The secret code is programmed and locked in the CAS control module and the DME control module. When the secret code is in the control modules, it can no longer be deleted or changed. This means that each control module is assigned to a certain vehicle. The CAS control module and the EWS control module mutually identify themselves with the secret number and the same algorithm. If the identification data is correct, the CAS control module activates the starter motor via a relay in the control module. At the same time, the CAS control module sends the DME control module a coded release signal (changing code) for the engine start. The DME control module only enables the engine start if a correct enable signal is received from the CAS control module. These procedures may result in a slight start delay (up to half a second).

NOTE: Procedure in the event of a defective control module.

If the CAS or DME is defective, a certain procedure must be followed. The required control module must be ordered exactly for the vehicle. For this, the vehicle data (vehicle identification number) is required. An EWS calibration is not necessary after renewing the control module.

Comfort start
Pressing the START-STOP button initiates the starting operation. The starter motor is only activated until the engine is running. If the engine does not start, the starting operation is aborted after approx. 60 seconds. The START-STOP button only picks up driver's requests. The starting operation is carried out by the CAS control module. The CAS only performs the engine start when all the start conditions have been met. If a condition is no longer met during the starting operation, the starting operation is aborted.

Control of the electrical steering interlock
During the unlocking procedure, an authentication procedure is run between the Car Access System (CAS) and the electrical steering interlock. The electrical steering interlock may only commence unlocking after a positive result in the authentication procedure. For safety reasons, the electrical steering interlock is not supplied with current while the vehicle is being driven. The electrical steering interlock is only supplied with voltage for the unlocking procedure or locking procedure.

Unlocking the electrical steering interlock
Switching on terminal R starts the unlocking procedure. After recognition of valid access rights, the CAS triggers the operation for unlocking the electrical steering interlock. First, the CAS switches the electrical steering interlock on. Then, the vehicle status and status of the electrical steering interlock are checked. Subsequently, a coded release for unlocking is sent. After receipt of the valid release, the electrical steering interlock initiates the unlocking procedure. The drive of the electrical steering interlock is activated towards "unlock".







The motor moves a driver via a single-stage gear. The driver pulls the locking bolt into the unlocked position until the securing lever locks into place. The end position of the securing lever is picked up by a Hall sensor. If the electrical steering interlock detects the position "unlocked and secured", the engine is stopped. This status is sent via K-CAN to the CAS. The CAS interrupts the power supply. When no current is applied, the securing lever is automatically locked.

NOTE: Start release by the Car Access System.

Start release is granted by the CAS control module. A start release is only granted after an fault free plausibility check. The CAS control module must detect the status "unlocked and secured" without faults. For an engine start, the CAS must have switched off the power supply to the electrical steering interlock.

NOTE: Unlocking with Comfort Access

On vehicles with Comfort Access, the remote control is also an identification sensor. To unlock the electrical steering interlock, a valid identification sensor must be detected in the inside of the vehicle.

Locking the electrical steering interlock
When all the conditions for locking have been met, the CAS initiates the locking procedure. The CAS switches the power supply for the electrical steering interlock on and checks its status. After a successful plausibility check of the status, the CAS sends the locking release to the electrical steering interlock. The locking procedure starts. The motor moves a driver via a single-stage gear. The driver pulls the locking bolt into the locked position until the securing lever locks into place. The end position of the securing lever is picked up by a Hall sensor. If the electrical steering interlock detects the position "not unlocked and secured", the engine is stopped. This status is sent via K-bus to the CAS. The CAS interrupts the power supply. When no current is applied, the securing lever is automatically locked. If the electrical steering interlock has already locked without faults, no locking procedure is executed. The electrical steering interlock once again sends the current status to the CAS control module.

NOTE: Interlock only after the vehicle is at a standstill.

The electrical steering interlock only locks when the following signals indicate the vehicle is at a standstill:
- Speed signal on the serial interface.
- Signal regarding the drive status on the CAN bus.

Both signals must indicate the vehicle is at a standstill. This plausibility check only takes place for the locking procedure.

Locking with Comfort Access
With Comfort Access, the vehicle is locked when the button on the outer door handle is touched. Here, the electrical steering interlock also locks. On vehicles with Comfort Access, the electrical steering interlock locks under the following conditions when the engine was started:
- Terminal 15 OFF
- Locking via the button in the outer door handle.

If the engine was not started, the electrical steering interlock locks after terminal R Off and door opening.

Or securing the vehicle if terminal R was on.

Central control of the central locking system
The CAS control module is the master control module for the central-locking system. On the basis of the operation request, the CAS decides whether the central-locking system is unlocked, locked or secured.

NOTE: Central double-locking only for certain country-specific options.

There is no motor for central double-locking in the US version.

The central-locking system of the doors, luggage compartment lid as well as fuel filler door is activated by the junction box electronics (JBE).

Central control of the power windows
The CAS is the master control module for the power windows. Due to the various national versions, the functions of the power windows are strongly dependent on the coding.

The power windows in the doors are activated via the footwell module (FRM).

Central control from Comfort Access (CA: comfort access)
With Comfort Access, an identification sensor is required instead of the usual remote control. The identification sensor also performs the usual functions of the remote control. Comfort Access can be used to run the following functions:
- Passive Entry
Opening the vehicle or luggage compartment without active use of the identification sensor
- Passive Go
Engine start without active use of the identification sensor
- Passive Exit
Closing the vehicle without active use of the identification sensor

The CAS control module is the master control module for functions run by Comfort Access. On vehicles with Comfort Access, a CA control module is fitted.

Central data source for the vehicle order and redundant data storage for vehicle data
The vehicle order is stored in the CAS. The vehicle order describes the type of vehicle, national version and optional extras. Redundant to the instrument cluster, the following are stored in the CAS:
- Vehicle identification number
- Status of the odometer
- Data for Condition Based Service (CBS)

The vehicle identification number and odometer serve to prevent manipulation. The CBS data is important for regular maintenance in service. The CBS data must not be lost. The CBS data is updated within a drive cycle in the ignition key or remote control.

A drive cycle is defined by:
- The first update is carried out when:
- Terminal 15 ON
- and speed at least once above 41 km/h
- and speed again fallen below 39 km/h

- Every other update is carried out when:
- a distance of more than 10 kilometers is driven
- and speed at least once above 41 km/h
- and speed again fallen below 39 km/h

In addition, a hidden service function can be used to update the CBS data on the remote control:
- Insert remote control -> Press and hold centre lock button -> Switch on terminal 15

Notes for Service department

General information

NOTE: Hidden service function in an emergency.

In the event of faults in the catch for the remote control, there is a hidden service function for switching on terminal R. This can be used to prevent non-starters . Press the START-STOP button for 10 seconds.

Diagnosis instructions
Observe the following information for diagnosis of the Car Access System:

Check of the remote control
The remote control can be checked using the BMW diagnosis system. If the remote control does not work, proceed as follows:
- First of all, try using another remote control that belongs to the vehicle
- Check the state of charge of the batteries in the remote control
- Measure the electrical field strength

The BMW diagnosis system can be use the control-module functions of the CAS to measure the electrical field strength of the remote control. To do so, one of the buttons of the remote control must be pressed. When a value for the field strength is read out, it means:
- the radio gap between the remote control and remote control receiver is OK; no interfering transmitter detected.
- the signal cable from the remote control receiver to the Car Access System (CAS) is OK.

NOTE: Declining field strength.

With increasing distance of the remote control from the vehicle, the measured field strength declines.

Notes on coding / programming
After replacement of the Car Access System (CAS), the following steps must be carried out:
- Programming the CAS
- Coding the CAS
- For diesel engines: run calibration with the DDE

The calibration between the CAS and the Digital Diesel Electronics (DDE) is located in the service functions. On calibration, the random codes for the electronic immobilizer (EWS, 3rd generation) are initialized.

Country-specific version
There is no motor for central double-locking in the US version.

No liability can be accepted for printing or other faults. Subject to changes of a technical nature.