Principle of Operation

Principle of Operation

Central Locking System Functions

Central Locking

Central locking is activated using the Central Locking button inside of the vehicle. Only the doors and trunk are locked, the fuel tank filler door remains open for access by gas station attendants. The locking pin in the door lock assembly is not disengaged, therefore the vehicle doors may be unlocked by pulling on the interior handle once.

Double Locking

When double locking is engaged, the locking pin in each door is disengaged from the lock by a mechanical coupling. It is no longer possible to unlock the vehicle from the inside using the handles or from the outside. The fuel-tank filler door is locked.

Double locking is only possible with terminal OFF and the subsequent opening of one of the front doors and with the driver's door closed, With the driver's door open, there is no action in response to the double locking operator request.

Selective Unlocking

Selective unlocking is activated by means of coding. With selective unlocking, only the driver's door is unlocked on the first unlocking command via the driver's door operating location or the remote control. The other doors move into the locked position. Only with the second unlocking attempt is the entire vehicle unlocked.

Double Unlocking with Valid Remote Control

With the vehicle double locked, the assemblies are moved from the "double locking" position to the "locked" position when a valid Remote Control is inserted in the CAS. The vehicle engine may only be started when the central locking has been double-unlocked.

The procedure is handled by the K-CAN messages for the central locking control system. If a driver has unintentionally locked himself inside his vehicle by means of the Remote Control,forced double unlocking prevents him from driving off in the vehicle while it is double-locked and the anti-theft alarm system is armed.

Double Unlocking via Central Lock Button (CLB)

An occupant who has accidentally locked himself in is able to get out by operating the CLB. This action moves the ZV on a one-off basis from double locked to locked. It is then possible to open the door through double operation of the inside door handle.

The DWA is not disarmed in this process so that when a vehicle is opened in this way an alarm cycle is triggered when the door is opened.

Electric Lock-Out Protection

With electric lock-out protection, the electronics ensures that the central-locking assembly is unlocked again e.g. when the locking knob is pressed down with an open driver's door. This protects the driver against being inadvertently locked out. With the driver's door open, it is not possible to lock the vehicle with the central lock button. The remote control is likewise ineffective.

Crash Unlocking

The crash message is transmitted from the Safety Information Module (SIM) via the ZGM to the K-CAN-S. The CAS receives the message and passes it on over the K-CAN-P.

The message is made available to the door modules and the Power Module. A priority "unlocking message" is simultaneously created by the ZV master in the CAS and forwarded to the door modules and the Power Module. This is to ensure that the system is unlocked in each case even if the crash message were to be delayed because of a a currently active message. Unlocking of the Central Locking system in the event of a crash is only permitted under the following conditions:

- Terminal R ON
- Terminal 15 ON
- Vehicle is not in double-locked state.(for theft protection)

Reactivation of Controls after Crash Unlocking

The following component signals are disabled after crash unlocking to prevent unwanted re-locking due to crash-induced short-circuit faults or damage of the lock mechanism:

- Lock cylinder, driver's door
- CLB
- Remote Control

These components are re-activated by resetting the CAS-internal crash status. After terminal R "OFF", the following events can reset the crash status after 3 s:

- Reception of signals "status, crash severity" value 0 (light collision without airbag activation)
- Opening and closing of driver's door
- Unlocking command at lock cylinder in driver's door
- Unlocking command via Remote Control
- Deactivation and reactivation of terminal R

Timed-Arrest

An timed arrest circuit is provided because the assembly motors are always operated up to their stops. An internal counter is increased by a value of 1 each time it is actuated. This counter is reduced by a value of 1 after a specified period of time.

The timed arrest circuit engages if the counter exceeds a specified value on account of permanent actuation. All the operator prompts for the Central Locking are forwarded but no longer executed.

The door modules and the Power Module signal via the K-CAN P to the Central-Locking master in the CAS that an assembly is now in timed arrest status. The ZV master in the CAS then outputs an overall status "ZV assembly, timed arrest circuit" for all the users.

The timed arrest circuit is disengaged by the door modules and the Power Module when the signal "ZV assembly, timed arrest circuit" is removed. There is also an timed arrest circuit for trunk-lid unlocking. The anti-repeat circuit is ignored during the crash unlocking function.

Initiation of Convenience Closing/Opening

The Central Locking system includes the convenience function for power windows and sliding sunroof. It is possible by means of the lock cylinder in the driver's door or by Remote Control to initiate sequential closing (only from drivers door) and opening of the windows and the sunroof as long as terminal R is off.

Convenience closing is initiated if a ZS (double-lock) command is held for an extended period. The sequence is aborted if the ZS command is cancelled during the closing operation. If a ZS command is entered again within a specific period since the cancellation, the sequence starts after a brief period.

Convenience opening is initiated if an ER (unlock) command is held for an extended period. The sequence is aborted if the ER command is cancelled. In the event of resumption, convenience opening follows the same process as convenience closing.

The Central Locking system forwards the operator prompts to controlling functions in the CAS (power-window master) and to the vehicle bus system.

Signalling to Anti-Theft Alarm System (via CAN)

The DWA is not part of the Central Locking system but it does require commands and signals from it. For this purpose, the DWA monitors the status of doors, hood, trunk and terminal status.

The DWA monitors the tilt sensor and the ultrasonic interior protection sensor by itself.

The DWA is armed by each valid locking (ZS) command. Optical feedback is provided by an LED, which signals the status of the DWA. The tilt and interior sensors are deactivated if a ZS command is initiated again within a specific period (10 s) after the first arming of the DWA.

The CAS forwards this information to the K-CAN P and K-CAN S. The DWA is disarmed by each double-unlocking command. The luggage compartment can also be accessed while the DWA is armed via remote control without the alarm being activated.

The alarm is activated if the trunk lid is opened mechanically using the emergency lock cylinder while the DWA is armed.

Scope of DWA monitoring from the Central Locking system:

- Door contacts
- Engine-hood contact
- Trunk-lid contact
- Tampering, driver's-door lock cylinder

Vehicle and Key Memory Individualization

All the codable functions for Vehicle/Key Memory are activated within the framework of the E65/E66 Coding, Individualization and Programming program (CIP).

These functions can be set using the coding software and are stored in the CAS. They only become active when the vehicle has been "double-locked".

The following central locking functions have been made possible for individualization (4 keys+1 vehicle coding):

- Selective unlocking of driver's door.
- Automatic locking from a speed of 16 km/h (10mph).
- Automatic relocking if vehicle unlocked by remote control and no ensuing action in 2 minutes.

Soft Close Automatic Doors (SCA)

The Soft Close Automatic Doors are optional equipment (part of the convenience package). The drive assemblies are integrated into the door locks and are controlled by the individual door modules.

There are 2 additional hall sensor signals for the position detection of the SCA drive:

1)"Stand-by" position

2)"Locking pawl switch" position

- The control system always knows the position of the drive and can, if necessary, activate it in order to move it to a defined or "set" position.

- The "Locking pawl switch" position is set each time the drive is switched on and deleted again when switched off in a set position (stand-by or park). The "Stand-by" position" is set when the door is opened and deleted when the latch has reached the park position.

- When the door is opened,(recognized by the rotary-latch hall sensor), the SCA drive moves into the stand-by position so that it only needs to move half a turn into the park position the next time the door is pulled closed. If the door is moved into the main catch before the SCA is in operation (slamming shut), the SCA drive remains in the stand-by position. The SCA does not move the next time the door is opened.

- When the door is closed, the sensors identify the catch position from the locking-pawl signal and pull the door into the main catch. The SCA drive then remains in the park position.

- If the electronics fails to identify the reaching of the two defined positions, the control system assumes a timeout after 5 s and shuts down the SCA drive. An entry is also made in the fault memory of the respective door module.

- The stop conditions are checked every 23 ms while the SCA is in operation. The motor is shut down if the SCA is not stopped within 5 s. The motor is switched off when reaching the park position.

Timed Arrest Circuit

The SCA doors have a timed arrest circuit to prevent the motors and final stages from overheating. Operation is staggered until the arrest counter in the door modules returns to zero.