Drive Authorization System (DAS), Function - GF80.57-P-0005KJ

MODEL 453.0/3/4 

Shown on drive authorization system (DAS)

Courtesy of MERCEDES-BENZ USA

Function requirements, general 

• Valid key (A8/1)

Drive authorization system, general 

The drive authorization system is intended to prevent unauthorized use of the vehicle. After switching on the ignition, the drive authorization is checked and the engine management released where applicable. In addition the vehicle can also be equipped with various additional functions for extended theft protection:

• Scanner protection (anti Scanning Protection)
• Dongle (Dongle code)
• Start refusal in event of vehicle theft (Stolen Vehicle Tracking) (vehicles with code P02 (car2go)) or code 54P (Line package rental model)

Function sequence for drive authorization system 

1. The ignition is switched on (2nd key position).
2. A frequency is superimposed on the transponder coil, which is supplied with power by the transponder magnetic field built up in the key.

   The communication between the transponder coil (L11) and the transponder is inductive and independent of the batteries in the transmitter key.

3. The center SAM control unit (N10/10) transmits a password and the number of the data block which is to be read out in the transponder via the transponder coil to the transponder in the transmitter key.
4. After receiving a valid password, the transponder is read out by the center SAM control unit and checked for validity.
5. If validity is recognized, enabling is signaled by the ME-SFI control unit (N3/10) (except model 453.091/391/491) or electric drive control unit (N127) (only model 453.091/391/491).
6. After this, the new content is written to the data block read out of the transponder.

The start is not enabled when:

• After ignition ON, the engine control unit does not recognize a request
• No acknowledgement signal recognized by the ME-SF control unit (except model 453.091/391/491) or electric drive control unit (only model 453.091/391/491)
• With invalid transponder code
• The energy for the transponder is not available

The drive authorization system is independent from the safety status of the central locking.

Scanner protection (anti Scanning Protection) 

In order not to outsmart the drive authorization system by checking several transponder codes, it is equipped with a scanner protection feature. For this purpose the ME-SFI control unit (except model 453.091/391/491) or electric drive control unit (only model 453.091/391/491) refuses start enable after 3 incorrectly transmitted transponder codes. To cancel this blocking, switch on ignition (c. 15) with correct transponder for min. 10 s and then switch back off for 30 s. (Run-on no longer active and ME-SFI control unit or electric drive control unit as well center SAM control unit in sleep mode). When the ignition is switched back on again, the start inhibit is canceled and the counter reset.

Dongle (Dongle code) 

When the ignition (c. 15 ON) is switched on, the center SAM control unit exchanges a dongle code with the telematics services communication module (N112/2) ("Tracker-ECU") and the electric power steering control unit (N68) ("Dongle-ECU") via the interior CAN (CAN B). If this code is not correct, because the center SAM control module has been replaced for example, the drive authorization system refuses start enable. This is accomplished by a software key between the center SAM control unit and ME-SFI control unit (except model 453.091/391/491) or electric drive control unit (only model 453.091/391/491). When the electric power steering control unit is replaced, it absolutely necessary to perform authentication for the new electric power steering control via an extended diagnostic with XENTRY Diagnostics.

Start refusal in event of vehicle theft (Stolen Vehicle Tracking) (vehicles with code P02 (car2go)) or code 54P (Line package rental model) 

In the subsequent text the following abbreviations are used: Subscriber Identification Module (SIM).

On c. 15 ON, the center SAM control unit exchanges the dongle ("Tracker-Code") with the telematics services communication module (N112/2) to enable start via the interior CAN. If the vehicle is stolen, it is possible to transmit a corresponding message to shut down the vehicle to the telematics services communication module via the mobile telephone network and the internal SIM card (e-SIM). When the telematics services communication module receives this message, the telematics services communication module refuses to communicate with the center SAM control unit when the next start attempt is made. Then the drive authorization system refuses the start enable. This is accomplished by an encrypted code between the center SAM control unit and ME-SFI control unit (except model 453.091/391/491) or electric drive control unit (only model 453.091/391/491). Due to reasons of safety, the vehicle can still be operated until the ignition is switched off next time. This is required to prevent accidents due to immediate shutdown of the vehicle. For this purpose the telematics services communication module receives the vehicle speed by the electronic stability program control unit (N30/4) via the interior CAN. When the telematics services communication module is replaced, it is necessary o perform an authentication of the new telematics services communication module via the extended diagnostic with XENTRY diagnostics.

	Electrical function schematic for drive authorization system (DAS)		PE80.57-P-2050-97BBA
	Overview of system components for theft protection and locking		GF80.00-P-9999KJ