Activating the anti-theft alarm
Illustration for a vehicle with an interior motion sensor (IMS), code 882
A26/14 - IMS Transceiver; B33 - Anti-theft alarm tilt sensor (ATA); H3/1 - Siren with additional battery; N10/6 - Left Front SAM; N10/7 - Right Front SAM; N10/8 - Rear SAM; N70 - Overhead console control unit; N72/1 - Upper console control unit; N72/1s7 - ATA, IMS and Towing Sensor (TS) Operation Indicator Switch; N73 - Electronic ignition/starter control unit; S62 - Hood open/close switch (ATA); S17/3 - Left door switch; S17/4 - Right door switch; S17/5 - Left rear door switch; S88/3 - Concealed microswitch for closing the luggage compartment lid; S17/6 - Right rear door switch
Anti-theft alarm
ATA is activated by:
- Single lock with remote control;
- Single lock with lock switch (USA, Japan);
- Re-closing;
- Locking with KEYLESS GO system (only code 889);
- Self-activation (Belgium): Two minutes after the last locking, if the driver's door is opened and closed again after the remote control key is removed;
- ATA does not activate when the driver's door is open;
- Activation of ATA interrupts the previous alarm;
- When power is applied again, the ATA is automatically reactivated if it was active before the power was interrupted;
- IMS and TS can be disabled separately.
Sequence of work
The EIS control unit (N73) issues a command on CAN to lock the vehicle. The left front SAM (N10/6) sends the message "ATA active" on CAN. The affected control units then activate their alarm inputs.
Siren activation with additional battery (H3/1)
The left front SAM (N10/6) activates the siren (H3/1) via a direct data bus.
Original source of information: MercedesMan.ru
Activation of contact with the outer surface
Rear (N10/8) and left front (N10/7) SAM activate the alarm inputs to which the door contacts are connected. The input is activated after at least 10 seconds of inactivity.
Other functions
When the rear SAM (N10/6) receives a message to lock all doors and the trunk lid, TS and IMS are also activated (if they were not previously turned off).
Feedback on successful activation
When ATA is active, the overhead console control unit (N72) causes the LED in the TS, IMS and ATA indicator switches (N72/1s7) to flash at a frequency of 1 Hz.
Activation of the TS towing sensor
The front left SAM (N10/6) transmits a command to the rear SAM (N10/8) to activate the TS. The TS input is activated by the rear SAM after at least 10 seconds of inactivity.
Code 882 only: Activation of the motion sensor in the IMS cabin
The front left SAM (N10/6) transmits a command to the overhead console control unit (N70) to activate the IMS transceiver (A26/14). The overhead console control unit activates the module directly via the data bus. The module indicates that it is ready for operation.