GF80.57-P-0003RT Drive Authorization System Level 3 (DAS (FBS) 3), Function

GF80.57-P-0003RT Drive Authorization System Level 3 (DAS [FBS] 3), Function

Component Identification:

Description
The drive authorization system stage 3 (DAS 3) is a system combination of control units consisting of:
^ EIS control unit
^ ME control unit
^ VGS control unit
^ Intelligent servo module for DIRECT SELECT

The encrypted data is exchanged between the transmitter key and the EIS control unit via infrared signal The code is computed in dialog between the transmitter key and the EIS control unit using the Hash method.

The corresponding Hash value of the transmitter key is transmitted to control units by the EIS control unit. Check, release and feedback is performed separately by each control unit.

Hash function
The encrypted base module is a so-called Hash function. The most important property of the Hash function is the one-way characteristic. This means that another number can be calculated using the Hash function from an initial number, however that calculation of the initial number in the opposite order is practically impossible.

Function
When inserted into the EIS control unit, the power supply to the transmitter key is established inductively via a coil in the EIS control unit so that the vehicle can be started even when the transmitter key battery is discharged.
Bi-directional infrared communication is accomplished between the transmitter key and the EIS control unit

The function buttons of the transmitter key are not active as long as the key is inserted in the EIS control unit

Transmitter key in position "A"
^ The inductive energy transmission to the voltage supply of the transmitter key is switched on.
^ Encrypted data exchange between transmitter key and EIS control unit for identification.

The next Hash values are calculated in the transmitter key. After completion of the calculation, the energy transmission is switched off. After positive identification the following is performed:
^ Release of lift solenoid for rotary lock in EIS control unit for transmitter key (up to 31.5.07)
^ Key position recognition switched on
^ Wake-up of controller area network bus class B (interior compartment) (CAN-B) and CAN-C
^ Output of circuit 15C

As of 1.6.07 the rotary lock in the EIS control module is eliminated. It is not possible to active any terminals with an incorrect transmitter key or a transmitter key which is not functioning properly. The note "Key does not belong to vehicle" appears in the instrument cluster.

Transmitter key in position "B"
^ Actuation of circuit 15R
^ Output of status circuit 15R to CAN-B and CAN-C

The transmitter key cannot be removed in position "B".

Transmitter key in position "C"
^ Circuit 15 is actuated
^ Output of status circuit 15 and circuit 15X to CAN-B and CAN-C
^ Encrypted request for ME-SFI Control unit
^ Encrypted request for VGS control unit
^ Encrypted request for intelligent servo module for DIRECT SELECT

The transmitter key cannot be removed in position "C".

Transmitter key in position "D"
^ Actuation of starter (M1) via ME-SFI control unit
^ Output of status for circuit 50 to CAN-B and CAN-C
^ C. 15X is removed from CAN-B and CAN-C until c. 50 is again off and the engine is running (c. 61)

The transmitter key automatically returns to position "C" when released

Take vehicle out of operation
Turning transmitter key back to left switches off the engine. The following functions are implemented in the EIS control unit:

Transmitter key in position "B"
^ Switch off signals circuit 15 and 15X
^ Adjust CAN C communication

Transmitter key in position "A"
^ Open load switch circuit 15R
^ Transmitter key can be removed (selector lever in position P).
^ The P-position of the transmission is actuated by the intelligent servo module for DIRECT SELECT.
^ Key-P-function: When the transmitter key is removed, the EIS control module requests the intelligent servo module for DIRECT SELECT to shift to drive stage "P" via the CAN-C

With code (889) Keyless Go:
When the driver door is open, the EIS control module sends a request to the intelligent servo module for DIRECT SELECT via CAN-C to shift to drive stage "P".

^ The emergency P path of the intelligent servo module for DIRECT SELECT is actuated by an error in the EIS control module or in the intelligent servo module for DIRECT SELECT. To ensure this function, a back-up battery is present, in addition to the primary power network The emergency P path is actuated via a switch in the EIS control module in the intelligent servo module for DIRECT SELECT, releasing a spring mechanism, making it possible to shift to transmission position P.

The EIS control unit can request a new check for identification of the transmitter key during restart without removing the key.

Memory block, memory block number, key dependency
The EIS control unit has 8 so-called key rails for operating 8 transmitter keys. One memory block number each is assigned to key rails 1, 2 and 3. The third memory block number is used when the key assignment is switched off and for key rails 3 to 8. The memory block number is required for key-dependent storage (e.g. adjusting the air conditioning or the instrument cluster (A1)).

Output of memory block number to CAN-B
Output of the memory block number is performed by the EIS control unit by:
^ Open central locking (CL) with transmitter key
^ Insert or remove transmitter keys from EIS control unit