Function requirements, general
Anti-theft alarm system (ATA) activated
The front SAM control unit (N10/6) transmits the status of the anti-theft alarm system via the interior (CAN B) to the overhead control panel control unit (N70) (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99 with code 882 (interior protection and tow-away protection)), to the control unit for the ATA/tow-away protection/interior protection (N26/6) (model 205.0/1/2/3 up to May 31, 2018 or model 253 (except 253.99) up to May 31, 2019, with code 882 (interior protection and tow-away protection)) or to the control unit for the ATA/tow-away protection/interior protection (N26/3) (model 205.4 up to May 31, 2018 with code 882 (interior protection and tow-away protection)).
ATA alarm triggering, general
If one of the alarm inputs changes its non-actuated state when the ATA is activated, the ATA alarm is triggered.
Action in event of undervoltage
The operating voltage range of the ATA has been defined from U = 8 up to 16 V. If the voltage drops below U = 8 V, a visual or acoustic alarm can no longer be output.
The ATA [ATA] alarm triggering function comprises the following partial functions:
Function sequence for alarm triggering by opening a door, trunk lid, liftgate or engine hood
Function sequence for alarm triggering by changing the vehicle inclination (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection))
Function sequence for alarm triggering if parking damage is detected (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection) in model 205 (except model 205.4) as of June 1, 2018 or in model 253 (except model 253.99) as of June 1, 2019 or in model 253.99)
Function sequence for alarm triggering by movement in the vehicle interior (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection))
Function sequence for alarm triggering due to glass breakage (model 205.2, 253 with code 882 (Interior protection and tow-away protection))
Function sequence for alarm triggering through loss of communication to alarm siren (H3/1) (with code (882) Interior protection and tow-away protection)
Function sequence for alarm triggering by panic alarm (with code (494) USA version)
Function sequence for alarm output
Function sequence for alarm triggering by opening a door, trunk lid, liftgate or engine hood
The front SAM control unit actuates an alarm so soon as the one of the following switches exits the non-actuated state:
Left front door rotary tumbler switch (A85s1) in left front door latch (A85)
Right front door rotary tumbler switch (A85/1s1) in right front door latch (A85/1)
Left rear door rotary tumbler switch (A85/3s1) (model 205.0/1/2, 253) in door latch for left rear door (A85/3) (model 205.0/1/2, 253)
Right rear door rotary tumbler switch (A85/4s1) (model 205.0/1/2, 253) in door latch for right rear door (A85/4) (model 205.0/1/2, 253)
Trunk lid/liftgate latch main catch switch (A85/5s1) in trunk lid/liftgate latch (A85/5)
Center console anti-theft alarm system switch group (S21) (model 205.4)
Hood contact switch on driver's side (S62/43)
The left front door control unit (N69/1) reads in the status of the left front door rotary tumbler switch directly and sends it to the front SAM control unit via interior CAN. The right front door control unit (N69/2) reads in the status of the right front door rotary tumbler switch directly and sends this via interior CAN to the front SAM control unit.
The rear SAM control unit (N10/8) reads in the status of the trunk lid/liftgate latch main catch switch directly and sends this via interior CAN to the front SAM control unit.
Model 205.0/1/2, 253:
The left rear door control unit (N69/3) reads in the status of the left rear door rotary tumbler switch directly and sends this via interior CAN to the front SAM control unit. The right rear door control unit (N69/4) reads in the status of the right rear door rotary tumbler switch directly and sends this via interior CAN to the front SAM control unit.
The front SAM control unit directly reads in the status of the center console anti-theft alarm system switch group (model 205.4) and the driver's side hood contact switch and evaluates the status of all other alarm inputs.
To trigger a new alarm, the corresponding switch must first change to the non-actuated state. After a non-actuated state of t = 10 s an alarm can be reactuated by the same switch, if an acoustic alarm is not present.
If a locked vehicle is unlocked with the emergency key and the door is opened, the ATA [ATA] triggers an alarm.
Additional functional requirement for alarm triggering by changing the vehicle inclination (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection))
Tow-away protection not deactivated
Function sequence for alarm triggering by changing the vehicle inclination (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection))
If the inclination sensor integrated into the overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or in the control unit for the ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) detects an alarm-relevant inclination change, an alarm is issued. The overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or the control unit for the ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) transmits a signal via the interior CAN to the front SAM control unit for this purpose.
Triggering criterion
Changing of the vehicle inclination (on the horizontal axes) to approx. 1.2°
Alarm is triggered before a wheel looses ground contact when lifting the vehicle.
Additional function requirements for alarm triggering if parking damage is detected (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection) in model 205 (except model 205.4) as of June 1, 2018 or in model 253 (except model 253.99) as of June 1, 2019 or in model 253.99)
Tow-away protection not deactivated
Function sequence for alarm triggering if parking damage is detected (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection) in model 205 (except model 205.4) as of June 1, 2018 or in model 253 (except model 253.99) as of June 1, 2019 or in model 253.99)
If the inclination sensor integrated into the overhead control panel control unit detects a physical shock that could have led to parking damage, a message showing the potential area of damage is issued.
To this end, the overhead control panel control unit sends, via the interior CAN, electronic ignition latch control unit (N73) and user interface CAN (CAN HMI) a signal to the head unit (A26/17). The head unit generates the corresponding image data and sends a switch-on request to the Audio/COMAND display via the telematics CAN (A) (A40/8). The image data is transmitted via the HSVL line to the Audio/COMAND display. The next time circuit 15 is switched on, a message to this effect is displayed on the Audio/COMAND display. The electronic ignition latch control unit transmits the status of circuit 15 via the user interface CAN to the head unit.
With code 362 (HERMES LTE), the overhead control panel control unit also transmits a signal via the interior CAN, electronic ignition latch control unit and diagnostic CAN (CAN D) to the HERMES control unit (N112/9). If the appropriate service has been activated, the HERMES control unit initiates a display on the customer's mobile phone.
Model 205, 253
with code 551 (Anti-theft warning system)
with code 852 (Sensor system for anti-theft alarm system (ATA))
The parking damage detection does not trigger an ATA alarm.
Additional function requirements for alarm triggering by movement in the vehicle interior (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection))
Interior protection not deactivated
Function sequence for alarm triggering by movement in the vehicle interior (with code 852 (sensor system for anti-theft alarm system (ATA)) or with code 882 (interior protection and tow-away protection))
Model 205.0/1/2/3 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99:
The left interior protection transmitter (N70a2) and right interior protection transmitter (N70a3) transmits ultrasonic signals into the vehicle interior. The ultrasonic signals are received by the interior protection receiver (N70a1). If a movement in the vehicle interior is recognized and considered to be alarm-relevant, an alarm is output. The overhead control panel control unit transmits a signal to the front SAM control unit via the interior CAN.
Model 205.0/1/2/3 up to May 31, 2018, model 253 (except model 253.99) up to May 31, 2019:
The left interior protection transmitter (N26/6b1) and the right interior protection transmitter (N26/6b2) send ultrasonic signals in the vehicle interior. The ultrasonic signals are received by the interior protection receiver (N26/6a1). If a movement in the vehicle interior is recognized and considered to be alarm-relevant, an alarm is output. The ATA [ATA]/tow-away protection/interior protection control unit sends the signal via interior CAN to the front SAM control unit.
Model 205.4:
The left front door interior protection sensor (B44/1), right front door interior protection sensor (B44/2), left rear interior protection sensor (B44/3) and right rear interior protection sensor (B44/4) send radar waves into the vehicle interior and receive the signals again. The signals are transmitted by the interior protection sensors via the alarm system LIN (LIN B14) to the overhead control panel control unit (as of June 1, 2018) or the ATA/tow-away protection/interior protection control unit (up to May 31, 2018). If a movement in the vehicle interior is recognized and considered to be alarm-relevant, an alarm is output. The overhead control panel control unit (as of June 1, 2018) or the ATA/tow-away protection/interior protection control unit (up to May 31, 2018) transmits a signal via the interior CAN to the front SAM control unit.
The sensitivity of the interior protection is reduced under the following circumstances:
Side window, panoramic sliding sunroof (with CODE 413 (Panoramic sliding sunroof)), sliding roof (with CODE 414 (Sliding roof)) or soft top (model 205.4) opened or denormalized
Active ventilation (e.g. evaporator drying)
Model 205, 253
with code 413 (Automatic panoramic sliding sunroof)
with code 551 (Anti-theft warning system)
Model 205, 253
with code 414 (Sliding sunroof)
with code 551 (Anti-theft warning system)
The vehicle interior is not monitored during active rain closing. After closing or after expiration of t = 35 s, the interior protection is reactivated. When the trunk lid is opened with the transmitter key (A8/1) the interior protection is deactivated. No monitoring of the vehicle interior compartment takes place during comfort closing (ultrasound switched off).
Function sequence for alarm triggering due to glass breakage (model 205.2, 253 with code 882 (Interior protection and tow-away protection))
The overhead control panel control unit (model 205.2 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or the control unit for the ATA/tow-away protection/interior protection (model 205.2 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) monitors the status of the following sensors:
Left rear window glass breakage sensor (B39)
Right rear window glass breakage sensor (B39/1)
Rear window glass breakage sensor (B39/4)
An alarm is output if an interruption is detected in the induction loop integrated in the glass of the respective side window in the rear by the overhead control panel control unit (model 205.2 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or by the control unit for the ATA/tow-away protection/interior protection (model 205.2 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019). The overhead control panel control unit (model 205.2 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or the control unit for the ATA/tow-away protection/interior protection (model 205.2 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) transmits the request to issue an ATA alarm via interior CAN to the front SAM control unit.
After an alarm is triggered by a glass breakage sensor, the other glass breakage sensors are deactivated (series circuit).
Function sequence for alarm actuation by communication loss to alarm siren (with code 882 (Interior protection and tow-away protection))
The alarm siren is cyclically addressed approx. every t = 600 ms by the overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or by the control unit for the ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) via the alarm system LIN. If the alarm siren does not respond (no communication) to this request within t = 1 s, the overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or the control unit for the ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) and the alarm siren trigger an alarm. If the alarm siren detects a loss of supply voltage, it also automatically emits an acoustic alarm.
The overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or the control unit for ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) transmits a signal via the interior CAN to the front SAM control unit.
Function sequence for alarm triggering by panic alarm (with code (494) USA version)
Vehicles without code (889) KEYLESS-GO and except code 893 (KEYLESS-GO start function):
Where the panic alarm button on the transmitter key is actuated for t 2 s, this transmits a radio signal via the rear window antenna (A2/32) and the antenna amplifier FM 1, AM, ZV and KEYLESS-GO (A2/18) to the electronic ignition latch control unit.
Vehicles with code (889) KEYLESS-GO or code (893) KEYLESS-GO start function:
Where the panic alarm button on the transmitter key is actuated for t 2 s, this transmits a radio signal via the rear window antenna and the antenna amplifier FM 1, AM, CL and KEYLESS-GO to the KEYLESS-GO control unit (N69/5). The KEYLESS-GO control unit sends this signal to the electronic ignition latch control unit via interior CAN.
The electronic ignition latch control unit checks the access authorization of the transmitter key and, if the access authorization code is valid, transmits the "Activate panic alarm" request via the interior CAN to the SAM control unit. The front SAM control unit actuates an ATA alarm.
The panic alarm is interrupted when the panic alarm button on the transmitter key is actuated briefly. The signal flow when the function is canceled is the same as when it is triggered.
Function sequence for alarm output
Visual alarm output
When an ATA alarm is triggered, the front SAM control unit activates the hazard warning flasher function via interior CAN. All turn signals are actuated synchronously on the vehicle.
Moreover, the front SAM control unit switches on the interior illumination.
Acoustic alarm output
The acoustic alarm is emitted on vehicles with code 882 (Interior protection and tow-away protection), through actuation of the alarm siren and for vehicles except code 882 (Interior protection and tow-away protection), through actuation of the left horn (H2) and the right horn (H2/1).
The alarm siren is actuated by the overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or by the control unit for the ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) via the alarm system LIN.
The overhead control panel control unit (model 205 as of June 1, 2018, model 253 (except model 253.99) as of June 1, 2019, model 253.99) or the control unit for ATA/tow-away protection/interior protection (model 205 up to May 31, 2018 or model 253 (except model 253.99) up to May 31, 2019) transmits a signal via the interior CAN to the front SAM control unit. The horns are actuated by the front SAM control unit via the horn relays (K40/8kL).
An alarm is only repeated if a new alarm event is registered after the active acoustic alarm was terminated. Three or ten alarms can be output in a severity cycle, depending on the national version (Belgium, Netherlands and Great Britain).
The acoustic alarm is activated for t = 30 s and the optical alarm for t = 300 s. On vehicles with code (833) Great Britain version, the acoustic alarm is extended to t = 300 s under the following conditions:
Interruption of power lines
If a door, the engine hood or trunk lid is broken open or remains open
Abort conditions: The alarm output is aborted if the CL is opened with the transmitter key or by inserting the transmitter key into the electronic ignition latch control unit or by pressing the KEYLESS-GO start/stop button (S2/3) (with code (889) KEYLESS-GO) or CODE 893 (KEYLESS-GO start function). The electronic ignition latch control unit transmits the status of the CL and the circuit status of circuit 15 to via the interior CAN to the front SAM control unit, which terminates the active alarm.
Alarm output on mobile phone (with code 362 (HERMES LTE))
If the appropriate service has been activated, the HERMES control unit initiates an alarm display on the customer's mobile phone. The alarm can also be deactivated via the mobile phone.
To this end, the overhead control panel control unit transmits a signal to the HERMES control unit via the interior CAN, electronic ignition latch control unit and diagnostics CAN.
Referenced documents
- gf8000p9999rf Overview of system components for theft protection and locking