GF80.61-P-3012CA Engine Start/Stop, Function

GF80.61-P-3012CA Engine Start/Stop, Function
- with CODE (889) Keyless Go


Function requirements, general
^ The transmitter key (A8/1) is located in the vehicle interior

Engine start/stop, general
With the engine start/stop function it is possible to start and shut down the engine with the KEYLESS-GO start/stop button (S2/3).

The engine start/stop function comprises the following subfunctions.
^ Function sequence for checking transmitter key
^ Function sequence for starting engine
^ Function sequence for display of fault messages
^ Function sequence for circuit switching
^ Function sequence for shutting off engine

Function sequence for checking transmitter key
If a door is opened and closed again, the electronic ignition lock control unit (N73) checks the transmitter key when starting to drive (v > 0 km/h) with the KEYLESS-GO control unit (N69/5). The transmitter key is checked after the last door is closed. If the vehicle is stopped without opening a door, a check is not performed again.

If a transmitter key is not recognized in the vehicle interior during this checking, the message "Key not recognized" appears in red lettering in the instrument cluster. In this case it is possible to switch off the engine, however, it cannot be started.

Additional function requirements for starting engine
^ Transmission in position "P" or "N"
^ Foot brake actuated

The electronic selector lever control unit (N15/5) transmits the status "Transmission selector lever in position P or N" via the drive CAN (CAN C). The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) relays it to the front SAM control unit with fuse and relay module via the chassis CAN (CAN E).N10/1

The front SAM control unit relays the status "Transmission in position P or N" to the KEYLESS-GO control unit () via the interior CAN (CAN B). The electronic stability program control unit (N30/4) (without code (233) DISTRONIC PLUS) or electronic stability program control unit Premium (N30/7) with code (233) DISTRONIC PLUS)) directly reads in the status of the brake light switch (S9/1) and provides it via the chassis CAN. The front SAM control unit forwards this via the interior CAN to the KEYLESS-GO control unit.

Function sequence for starting engine
The engine start/stop function is activated by pressing the KEYLESS-GO start/stop button. The electronic ignition lock control unit reads in the status of the KEYLESS-GO start/stop button and transmits it to the KEYLESS-GO control unit via the interior CAN.
The KEYLESS-GO control unit then transmits wake-up and location finding signals via the following components to the transmitter key:
- Left front door KEYLESS-GO antenna (A2/38)
- Left front door KEYLESS-GO antenna (A2/40)
- trunk Keyless-Go antenna (A2/35)
- interior Keyless-Go antenna (A2/61)

The transmitter key transmits its access authorization code and position to the KEYLESS-GO control unit via the following components:
- TV 2 and KEYLESS-GO antenna amplifier (A94/2) (model 207.3)
- Rear KEYLESS-GO antenna (A97) (model 207.4)

The KEYLESS-GO control transmits this data to the electronic ignition lock control unit via the interior CAN.
The electronic ignition switch control unit checks the access authorization of the transmitter key. If it is defined as valid and the transmitter key is located in the vehicle interior, it switches the corresponding circuits and the engine is started over the CDI control unit or ME-SFI control unit.

Function sequence for display of fault messages
Following situations leads to error message output:
- When a transmitter key is not located in the vehicle interior when an attempt is made to start the vehicle, the message "Key not recognized" is output on the instrument cluster (A1) multifunction display. The start attempt is not started. The status of the circuit remains unchanged.
- If, during a start attempt, the transmission is not in position "P" or "N", an acoustic warning tone sounds and a corresponding message is output to the instrument cluster.

If a transmitter key is not recognized in the vehicle interior during this interrogation, the message "Key not recognized" appears in red lettering in the instrument cluster. In this case it is possible to switch off the engine, however, it cannot be started.

Function sequence for circuit switching
If the foot brake is not depressed when the KEYLESS GO start/ stop button is actuated, only circuit 15R is switched on. Repeated actuation of the KEYLESS-GO start/stop button activates circuit 15. Actuating again, switches off circuit 15R and circuit. If the driver door is closed, circuit 15C remains active for t = 30 min.

Function sequence for shutting off engine
The running engine can be switched off by pressing the KEYLESS-GO start/stop button. For this purpose the electronic ignition lock control unit directly reads in the KEYLESS-GO start/ stop button and transmits the circuit status "Circuit 15 OFF" to the KEYLESS-GO control unit via the interior CAN.

The KEYLESS-GO control unit transmits the request to shut off the engine to the CDI control unit and ME-SFI control unit over the following path:
- Interior CAN
- Electronic ignition switch control unit
- Chassis CAN

The CDI control unit then shuts off the engine depending on the vehicle speed.

Switching off engine depending on vehicle speed:
- Speed below v = 3 km/h: Engine switched off immediately.
- Speed above v = 3 km/h: Engine is switched off after pressing KEYLESS-GO start/stop button for t > 3 s.

The instrument cluster transmits the vehicle speed information to the KEYLESS-GO control unit via the interior CAN.