Activate antitheft alarm system, function

Function requirements, general

 Circuit 15C OFF

 Central locking (CL) functioning properly

Activate antitheft alarm system (ATA [EDW]), general

The ATA is automatically activated with the CL when the vehicle is locked. Then the individual alarm inputs are monitored. The activated ATA [EDW] is indicated by the ATA [EDW] function indicator (N721e2) permanently flashing in the upper control panel control unit (N721). The SAM control unit (N10) actuates the ATA function display via the battery sensor LIN (LIN B15).

 Before locking the CL on vehicles with code (882) Interior monitoring (only with ATA), the tow-away protection or interior protection can be deactivated.

Activation of the ATA [EDW] comprises the following partial functions:

 Function sequence for activating ATA [EDW]

 Function sequence for switching off tow-away protection of ATA [EDW] (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for switching off interior protection of ATA [EDW] (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for activating alarm inputs

Function sequence for activating ATA [EDW]

The ATA is activated when the CL is locked. The electronic ignition lock control unit (N73) transmits the CL status via the interior CAN (CAN B) to the SAM control unit and ATA/tow-away protection/interior protection control unit (N26/6) (with code (882) Interior monitoring (only with EDW)). Then the ATA is activated.

 Special case: Driver door

If the driver door is still open when the CL is locked, it is not locked. After the driver door is closed, the left front door control units (N69/1) transmits the status of the driver door to the SAM control unit via the interior CAN. The alarm input is included in the polling cycle. This leads to actuation of an alarm when opening the driver door without previous deactivation of the ATA [EDW].

 Detailed information on locking the CL is given in the separate partial function "Central locking (CL), function".

Additional function requirements for tow-away protection of ATA (with code (882) Interior monitoring (only with ATA))

 ATA [EDW] not yet activated

Function sequence for switching off tow-away protection of ATA [EDW] (with code (882) Interior monitoring (only with ATA [EDW]))

The tow-away protection is switched off by actuating the tow-away protection button (S93/3s1) in the anti-theft alarm/emergency call system button group (S93/3) before the vehicle is switched off via the CL.

The overhead control panel control unit (N70) directly reads in the status of the tow-away protection button directly and transmits it over the roof LIN (LIN B13) to the SAM control unit. The SAM control unit transmits the status of the tow-away protection button via the interior CAN to the ATA/tow-away protection/interior protection control unit. It deactivates the tow-away protection for the following activation of the ATA [EDW].

Deselection of the tow-away protection is confirmed by an LED in the tow-away protection button for approx. t = 2 s after releasing the tow-away protection button.

Additional function requirements for switching off interior monitoring of ATA [EDW] (with code (882) Interior monitoring (only with ATA [EDW]))

 ATA [EDW] not yet activated

Function sequence for switching off interior protection of ATA [EDW] (with code (882) Interior monitoring (only with ATA [EDW]))

The interior protection is switched off by actuating the interior protection button (S93/3s3) on the anti-theft alarm /emergency call system button group before locking the vehicle via the CL.

The overhead control panel control unit directly reads in the status of the interior protection button and transmits it to the SAM control unit via the roof LIN. The SAM control unit transmits the status of the interior protection button via the interior CAN to the ATA [EDW] /tow-away protection/interior protection control unit. It deactivates the interior protection for the following activation of the ATA [EDW].

Deselection of the interior protection is confirmed by an LED flashing in the interior protection button at f = 6.25 Hz (t = 80 ms ON, t = 80 ms OFF) for approx. t = 2 s.

Additional function requirements for activating alarm inputs

 ATA [EDW] activated

Function sequence for activating alarm inputs

Activating alarm input function comprises the following subfunctions:

 Function sequence for monitoring switch

 Function sequence for activating tow-way protection (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for activating interior protection (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for activating alarm siren (H3/1) (with code (882) Interior monitoring (only with ATA [EDW]))

Function sequence for monitoring switch

The status (open or closed) of the following switched is checked cyclically every t = 200 ms:

 Left front door rotary tumbler switch (A85s1) in left front door lock (A85)

 Right front door rotary tumbler switch (A85/1s1) in right front door lock (A85/1)

 Left rear door rotary tumbler switch (A85/3s1) in left rear door lock (A85/3)

 Right rear door rotary tumbler switch (A85/4s1) in right rear door lock (A85/4)

 Trunk lid/liftgate lock main catch switch (A85/5s1) in trunk lid/liftgate lock (A85/5)

 Center engine hood contact switch (S62)

The left front door control unit reads in the status of the left front door rotary tumbler switch directly and transmits it to the SAM control unit over the interior CAN.

The right front door control unit (N692) directly reads in the status of the right front door rotary tumbler switch and transmits it to the SAM control unit over the interior CAN (CAN B).

The rear SAM control unit directly reads in the status of the rear door rotary tumbler switch, trunk lid/liftgate loch main catch switch and the status of the center engine hood contact switch.

The SAM control unit evaluates the status of all alarm inputs. If the polls indicate that an input is at rest within t = 10 s, the corresponding input is then armed.

Alarm inputs set later to the non-actuated state, e.g. if the trunk lid or liftgate is closed only after the vehicle has been locked, are also armed t = 10 s after closing.

Function sequence for activating tow-way protection (with code (882) Interior monitoring (only with ATA [EDW]))

The tow-away protection is activated t = 10 s after the CL is locked and the last door is closed and the trunk lid or liftgate is activated (if not previously deselected for the next locking operation).

The inclination sensor in the ATA [EDW] control unit/two-away protection/interior protection control unit determines a reference position, with which the relative vehicle inclination is compared during the activation. Determination of the reference position requires approx. t = 10 to 15 s, for this reason an alarm can only be triggered t = 20 s at the earliest after arming the ATA [EDW] .

When the maximum vehicle inclination is exceeded with regard to the reference position, an alarm is triggered.

If the vehicle inclination changes very slowly (e.g. leaky tire), the reference position adapts to the current vehicle position to prevent inadvertent activation of the inclination sensor.

If the inclination sensor is faulty, all other components of the ATA [EDW] continue to function properly and the corresponding fault codes are entered in the fault memory in the ATA [EDW]/tow-away protection/interior protection control unit.

Function sequence for activating interior protection (with code (882) Interior monitoring (only with ATA [EDW]))

The interior protection is activated t = 10 s after the CL is locked and the last door is closed and the trunk lid or liftgate is activated (if not previously deselected for the next locking operation).

The interior protection is ready for an alarm only after another t = 10 s, because it is first necessary to calibrate the ATA [EDW]/tow-away protection/interior protection control unit to match the vehicle interior.

If a defect is detected, the remaining ATA functions are still ensured regardless of this error. The corresponding fault codes are stored in the fault memory of the ATA [EDW]/tow-away protection/interior protection control.

Function sequence for activating alarm siren (with code (882) Interior monitoring (only with ATA [EDW]))

The alarm siren is armed together with the ATA [EDW] approx. every t = 600 to ms and checked cyclically by the ATA [EDW]/tow-away protection/interior protection control via the alarm system LIN (B14).

 Deactivating ATA:
The ATA [EDW] is deactivated completely by opening the CL with the transmitter key via infrared or by inserting a transmitter key into the electronic ignition lock control unit. The electronic ignition switch control unit transmits the corresponding signal with interior CAN to the rear SAM control unit, which then activates the ATA [EDW] .