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 central locking (CL) when the vehicle is locked. Then the individual alarm inputs are monitored. On vehicles up to 31.5.13, the activated ATA is indicated by permanently flashing antitheft alarm system indicator lamp (S6/1e2) in the instrument panel switch group (S6/1) or on vehicles as of 1.6.13 by a permanently flashing antitheft alarm system indicator lamp (N72/1e2) in the upper control panel control unit (N72/1). The antitheft alarm indicator lamp is actuated by the rear SAM control unit with fuse and relay module (N102) via the interior CAN (CAN B) and front SAM control unit with fuse and relay module (N10/1).

 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 status of the CL to the rear SAM control unit via the interior CAN (CAN B). 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 closing the driver door, the left front door control unit (N69/1) sends the status of the driver door via interior CAN to the SAM control unit. 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 not 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 (N70/3s9) (model 207.3) or tow-away protection button (S85/2s2) (model 207.4) in the overhead control panel electronic circuitry (N70/3) before locking the vehicle with the CL.

Model 207.3:

The interior protection and tow-away protection control unit (N26/6) directly reads in the status of the tow-away protection button and transmits it to the rear SAM control unit via the rear SAM-LIN (LIN B4). Then the rear SAM control unit deactivates the tow-away protection for the following activation of the ATA.

Model 207.4:

The interior protection sensor (Master) (A26/13) directly reads in the status of the tow-away protection button and deactivates the tow-away protection for the next activation of the ATA.

Then the interior protection sensor (Master) transmits the status "Tow-away protection deactivated" to the rear SAM control unit via the rear SAM-LIN.

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

On model 207.3 the rear SAM control unit transmits the request for visual feedback via the rear SAM-LIN to the interior protection and tow-away protection control unit, which correspondingly actuates the LED in the tow-away protection button.

On model 207.4 the rear SAM control unit transmits the request for visual feedback via the rear SAM-LIN to the interior protection sensor (master), which correspondingly actuates the LED in 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 not 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 (N70/3s8) (model 207.3) or interior protection button (S85/2s1) (model 207.4) in the overhead control panel electronic circuitry before locking the vehicle with the CL.

Model 207.3:

The interior protection and tow-away protection control unit directly reads in the status of the interior protection button and transmits it to the rear SAM control unit via the rear SAM-LIN (LIN ). Then the rear SAM control unit deactivates the interior protection for the following activation of the ATA.

Model 207.4:

The interior protection sensor (master) directly reads in the status of the interior protection button, deactivates the interior protection for the following activation of the ATA and transmits the corresponding request to interior protection sensor (slave) (A26/15).

Then the interior protection sensor (Master) transmits the status "Interior protection deactivated" to the rear SAM control unit via the rear SAM control unit.

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

On model 207.3 the rear SAM control unit transmits the request for visual feedback via the rear SAM-LIN to the interior protection and tow-away protection control unit, which correspondingly actuates the LED in the tow-away protection button.

On model 207.4 the rear SAM control unit transmits the request for visual feedback via the rear SAM-LIN to the interior protection sensor (master), which correspondingly actuates the LED in the tow-away protection button.

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 (H31) (on model 207.3 up to 31.5.10, model 207.3 as of 1.6.10 without code (494) USA version, model 207.4 without code (494) USA version)

Function sequence for monitoring switch

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

 Engine hood switch pedestrian protection + ATA Hall sensor (A38/1) (with code (U60) Pedestrian protection)

 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)

 Trunk lid rotary tumbler switch (M14/7s1) in trunk lid central locking motor (M14/7)

 Left engine hood contact switch (S62/43) (without code (U60) Pedestrian protection)

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

The right front door control unit (N69/2) reads in the status of the right front door rotary tumbler switch and transmits it to the rear SAM control unit via the interior CAN (CAN B).

The rear SAM control unit directly reads in the status of the trunk lid rotary tumbler switch or the status of the pedestrian protection Hall sensor + ATA [EDW] engine hood switch (with code (U60) pedestrian protection) or left engine hood contact switch (without code (U60) Pedestrian protection).

The rear SAM control unit evaluates the status of all alarm outputs. 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 is closed only after the CL 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 (if not previously deselected) after t = 10 s after the closing command from the electronic ignition lock control unit and after the last door or the trunk is closed. An inclination sensor is integrated into the interior protection and tow-away protection control unit (model 207.3) or interior protection sensor (master) (model 207.4) communicating with the rear SAM control unit or rear SAM-LIN. This inclination sensor determines the reference position, which is compared with the relative vehicle inclination. Determination of the reference position takes approx. t = 10 up to 15 s.

For this purpose an alarm can be actuated approx. t = 30 s after arming at the earliest. 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 defective, all other components of the ATA remain operable. The corresponding fault codes are stored in the fault memory in the rear SAM control unit.

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

The interior compartment is monitored by ultrasonic waves on model 207.3 and radar waves on model 207.4. The interior protection is activated (if not previously deselected) t = 10 s after the last door or the trunk is closed. After another t = 20 s the interior protection is ready for alarm. The interior protection and tow-away protection control unit (model 207.3) or interior protection sensors (model 207.4) must be calibrated to the interior compartment first.

 The interior protection sensors (model 207.4) operate according to the master-slave principle. The interior protection sensor (Master) is located below the center console and monitors the front interior compartment. The Interior protection sensor (slave) is located below the rear stowage compartment and monitors the rear interior compartment.

The status of the interior protection and tow-away protection or interior protection sensor (master) is monitored by the rear SAM control unit. 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 in the rear SAM control unit.

Function sequence for activating alarm siren (on model 207.3 up to 31.5.10, model 207.3 as of 1.6.10 without code (494) USA version, model 207.4 without code (494) USA version)

The alarm siren is armed together with the ATA [EDW] and checked cyclically approx. every t = 700 ms by the rear SAM control unit with rear SAM-LIN.

 Deactivating ATA:

The ATA is deactivated completely by opening the CL with transmitter key with infrared or radio or by switching on circuit 15C (valid transmitter key in electronic ignition lock control unit). The electronic ignition switch control unit transmits the corresponding signal with interior CAN to the rear control unit, which then activates the ATA.