Activate antitheft alarm system, function

Function requirements, general

 Circuit 15C OFF

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 for Belgium, the ATA arms automatically without locking the vehicle with the CL.

Activation of the ATA function comprises the following partial functions:

 Function sequence for activating ATA [EDW]

 Function sequence for switching off tow-way protection of ATA (with code 882 (Interior protection and tow-away protection))

 Function sequence for switching off interior protection of ATA (with code 882 (Interior protection and tow-away protection))

 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) sends the status of the central locking (CL) to the rear SAM control unit with fuse and relay module (N10/2) via the interior CAN. Then the ATA is activated. The rear SAM control unit transmits the status of the ATA via the interior CAN to the front SAM control unit with fuse and relay module (N10/1). The activated ATA [EDW] is indicated by the ATA [EDW] function indicator (N72/1e3) permanently flashing in the upper control panel control unit (N72/1). The front SAM control unit actuates the ATA function display via the instrument panel LIN (LIN 1).

 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 door control unit (N69/1) sends the status of the driver door via interior CAN to the rear 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 the function sequence for locking the CL, is given in a separate document.

 Model 190
with code 551 (Anti-theft warning system)
with code P17 (KEYLESS-GO package)
Detailed information for locking CL via KEYLESS-GO is given in a separate document.

 Self-arming (only vehicles for Belgium): If the driver door or liftgate is opened and closed again after removing the transmitter key (A8/1) from the electronic ignition lock control unit, the ATA is armed automatically after t = 100 s after the last door or the liftgate or trunk lid is closed, regardless of the locking status of the vehicle.

Additional function requirements for switching off tow-away protection of ATA with CODE 882 (Interior protection and tow-away protection))

 ATA [EDW] not yet activated

Function sequence for switching off tow-way protection of ATA (with code 882 (Interior protection and tow-away protection))

The interior protection control unit and tow-away protection control unit (N26/6) directly reads in the status of the tow-away protection button (N70/3s9) into the overhead control panel electronic circuitry (N70/3) and transmits the status of the function via the alarm system LIN (LIN B14) to the rear SAM control unit. Then the rear SAM control unit deactivates the tow-away protection for the following activation of the ATA.

Function feedback:

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. The rear SAM control unit transmits the request for this via the alarm system LIN to the interior protection and tow-away protection control unit, which correspondingly actuates the LED in the tow-away protection button.

Additional function requirements for switching of interior protection of ATA (with code 882 (Interior protection and tow-away protection))

 ATA [EDW] not yet activated

Function sequence for switching off interior protection of ATA (with code 882 (Interior protection and tow-away protection))

The interior protection and tow-away protection control unit directly reads in the status of the interior protection button (N70/3s8) into the overhead control panel electronics and transmits the function status via the alarm system LIN to the rear SAM control unit. Then the rear SAM control unit deactivates the interior protection for the following activation of the ATA. In addition, the monitoring of the rear window glass breakage sensor (B39/4) is deactivated in model 190.3.

Function feedback:

Deselection is confirmed by an LED in the interior protection button for approx. t = 2 s after releasing the interior protection button. The rear SAM control unit transmits the request for this via the alarm system LIN to the interior protection and tow-away protection control unit, 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 partial function comprises the following subfunctions:

 Function sequence for monitoring switch

 Function sequence for activating tow-away protection (with code 882 (Interior protection and tow-away protection))

 Function sequence for activating interior protection (with code 882 (Interior protection and tow-away protection))

 Function sequence for activating alarm siren (H3/1) (with code 882 (Interior protection and tow-away protection))

Function sequence for monitoring switch

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

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

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

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

 Left engine hood contact switch (S62/43)

 Glove compartment anti-theft alarm system switch (S62/7) (on model 190.4)

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

The left door control unit reads in the status of the left engine hood contact switch directly and sends it via interior CAN to the rear SAM control unit.

The rear SAM control unit directly reads in the status of the trunk lid/liftgate lock main catch switch and the status of the glove compartment anti-theft warning system switch (on model 190.4) and evaluates the status of all other alarm inputs.

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

Function sequence for activating tow-away protection (with code 882 (Interior protection and tow-away protection))

The tow-away protection is activated (if not deselected for the next locking) t = 60 s after locking the central locking system and closing the last door and liftgate or trunk lid.

The inclination sensor in the interior protection control unit determines a reference position, with which the relative vehicle inclination is compared during the activation. Determination of this reference position takes approx. t = 10 to 15 s. Therefore an alarm can only be triggered approx. t = 60 s after the ATA is activated, 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 vehicle inclination sensor is faulty, all other components of the ATA continue to function properly and the corresponding fault codes are entered in the fault memory in the rear SAM control unit.

Function sequence for activating interior protection (with code 882 (Interior protection and tow-away protection))

The interior protection is activated (if not deselected for the next locking) only t = 10 s after locking the CL and closing the last door and the liftgate or the trunk lid. The interior protection is ready for an alarm after another t = 10 s because the interior protection control unit and tow-away protection must first calibrate to match the vehicle interior. In addition, the monitoring of the rear window glass breakage sensor is activated in model 190.3. The status of the rear window glass breakage sensor (model 190.3) is directly read in by the interior protection and tow-away protection control unit.

If a defect is detected, the remaining ATA functions are still ensured regardless of this error. The corresponding fault codes are entered in the fault memory of the rear SAM control unit.

Function sequence for activating alarm siren (with code 882 (Interior protection and tow-away protection))

The alarm siren is armed together the ATA and checked cyclically approx. every t = 600 ms by the rear SAM control unit via the alarm system LIN.

 P17Deactivate ATA: A complete deactivation of the ATA occurs by opening the CL with the transmitter key via radio or by inserting the transmitter key in the electronic ignition lock control unit or by pressing the KEYLESS-GO start/stop button (S2/3) (with CODE (KEYLESS-GO)). The electronic ignition switch control unit transmits the corresponding signal with interior CAN to the rear control unit, which then activates the ATA.