GF80.57-P-0003CE Drive Authorization System Level 3 DAS(FBS) 3, Function
GF80.57-P-0003CE Drive Authorization System Level 3 (DAS[FBS] 3), Function
MODEL 204.0 /2 as of model year 2009 /YoM 08
MODEL 204.3
MODEL 204.9
A8/1 Transmitter key
N3/9 CDI control unit (with diesel engine)
N3/10 ME-SFI [ME] control unit (with gasoline engine)
N26/5 Electric steering lock control unit
N73 Electronic ignition switch control unit
Y3/8n4 Fully integrated transmission-control control unit (with transmission 722.9)
CAN B Interior CAN
CAN C Drive train CAN
CAN E Chassis CAN
Positions of transmitter key in electronic ignition lock control unit
A8/1 Transmitter key
N73 Electronic ignition switch control unit
Function requirements, general
^ Circuit 30 ON
^ Valid transmitter key inserted into electronic ignition lock control unit
Drive authorization system, stage 3 (DAS [FBS] 3), general
The DAS [FBS] 3 allows the ignition to be switched on and the engine to be started. The DAS [FBS] 3 is a compound system consisting of control units, each of which calculate and compare the drive authorization code independently.
If the check in question is valid, each component is released automatically.
The following control units are integral parts of the DAS [FBS] 3 system:
- Electronic ignition lock control unit
- Electric steering lock control unit
- CDI control unit (with diesel engine) or - ME-SFI [ME] control unit (with gasoline engine)
- Fully integrated transmission-control control unit (with transmission 722.9)
The DAS [FBS] 3 comprises the following partial functions:
^ Function sequence for switching circuit 15C (transmitter key in position "A")
^ Function sequence for switching circuit 15R (transmitter key in position "B")
^ Function sequence for switching circuit 15 (transmitter key in position "C")
^ Function sequence for switching circuit 50 (transmitter key in position "D")
^ Deactivating circuits
Function sequence for switching circuit 15C (transmitter key in position "A")
When the transmitter key is inserted into the electronic ignition lock control unit, it switches on the inductive power transmission (power supply to the transmitter key). The transmitter key and the electronic ignition lock control unit exchange encrypted data via infrared for identification of the transmitter key.
The identification code is computed in dialog between transmitter key and the electronic ignition lock control unit using the so-called Hash method.
The electronic ignition lock control unit transmits the hash value to the other control units involved.
Check, release and feedback is performed separately by each control unit.
The hash method is single-way encryption which prevents the vehicle from being started with an invalid transmitter key. With this method a new number combination is calculated from the old number combination. It is not possible to calculate vice versa.
Number combinations already calculated cannot be calculated again.
The electronic ignition lock control unit already calculates the next hash values. After end of calculation, the electronic ignition lock control unit switches off power transmission.
The following occurs after positive identification of the transmitter key:
- Key position recognition switched on
- Waking up Controller Area Network (CAN)
- Output of circuit 15C
- Unlocking steering lock with electric steering lock control unit
The vehicle can be started when the battery in the transmitter key is discharged.
The function keys of the transmitter key are not active as long as the electronic ignition lock control unit is inserted.
A message is output in the instrument cluster (A1) if an invalid transmitter key is used.
Function sequence for switching circuit 15R (transmitter key in position "B")
Circuit 15R is actuated by turning transmitter key to position "B".
The terminal status 15R is output via all CAN data buses.
The steering lock is locked by the electric steering lock control unit. The transmitter key can no longer be removed in position "B".
Function sequence for switching circuit 15 (transmitter key in position "C")
When the transmitter key is turned to position "C", terminal 15 is actuated.
Terminal status 15 is output via all CAN data buses. Power intensive consumers are supplied by circuit 15X
Parallel to this, an encrypted DAS [FBS] 3 query is sent to the ME control unit or CDI control unit and the fully integrated transmission control unit.
Function sequence for switching circuit 50 (transmitter key in position "D")
The starter (M1) is actuated via the ME control unit or CDI control unit by turning the transmitter key to position "D".
Terminal status 50 is output via all CAN data buses.
Terminal 15X is removed from the corresponding CAN until terminal 50 is OFF and the engine is running (time control, if applicable).
When circuit 15X is switched off, the electrical consumers are switched off to facilitate starting the engine.
The transmitter key automatically returns to position "C" when released.
Deactivating circuits
Turning transmitter key back to left switches off the engine. The following functions are implemented in the electronic ignition lock control unit:
- Transmitter key in position "B"
Switch off signals from circuit 15 and circuit 15X
- Transmitter key in position "A"
- Circuit 15R OFF
Transmitter key can be removed, steering lock locked with electric steering lock control unit (on vehicles with transmission 722 the transmitter key can only be removed when the selector lever is in position "P")
The electronic ignition lock control unit can request a new check for identification of the transmitter key during restart without previously removing the transmitter key.
