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Home >> Mercedes Benz >> 2009 >> C 350 (204.056) V6-3.5L (272.961) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Antitheft and Alarm Systems >> Keyless Entry >> Description and Operation >> GF80.61-P-3012CE Engine Start/Stop, Function

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



GF80.61-P-3012CE Engine Start/stop, Function

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
^ Display of fault messages function sequence
^ 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.A1 In this case it is possible to switch off the engine, however, it cannot be started.

Additional function requirements for starting engine
^ Selector lever position "P" or "N", from the electronic selector lever module control unit (N15/5) (with transmission 722)
^ Foot brake actuated (signal from electronic stability program control unit (N30/4))

Function sequence for starting engine
The status of the selector lever position is output by the electronic selector lever module control unit on the drive train CAN (CAN C). The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) reads in the status of the selector lever position and relays it to the electronic ignition lock control unit via the chassis CAN (CAN E).
The status of the brake light switch (S9/1) is read in by the electronic stability program control unit and relayed via the chassis CAN to the electronic ignition lock control unit.

When the KEYLESS GO start/stop button is pressed, the signal "Start engine" is transmitted to the electronic ignition lock control unit. It transmits the signal to the KEYLESS-GO control unit via interior CAN (CAN B)

The KEYLESS-GO control unit then transmits over the
- trunk Keyless-Go antenna (A2/35)
- Left rear door KEYLESS GO antenna(A2/39)
- Right rear door KEYLESS GO antenna(A2/41)
- interior Keyless-Go antenna (A2/61)

Wake-up and locating signals to transmitter key

The transmitter key transmits its access authorization code and position to the TV 2 and KEYLESS-GO antenna amplifier (A94/2) (model 204.0/9) or KEYLESS-GO antenna amplifier(A94/4) (model 204.2), which relays information to the KEYLESS-GO control unit. The KEYLESS GO control unit transmits the access authorization code to the electronic ignition lock control unit via interior CAN.

If the access authorization code is valid, circuit 15 is switched on and the engine is started by the CDI control unit or ME control unit.

Function sequence for error message display
If the transmitter key is not recognized in the interior compartment when an attempt is made to start the vehicle, the travel distance display (A1p7) (model 204.0/2/9 (except 204.077/277) without code (442) Comfort multifunction steering wheel) or in the multifunction display (A1p13) (with code (442) Comfort multifunction steering wheel, model 204.077/277) in the instrument cluster with the not "Key not recognized" is displayed and the start attempt is interrupted. The status of the circuit remains unchanged. If the electronic selector lever module is not in position "P" or "N" when the engine is started, a chime sounds and a corresponding text appears in the instrument cluster multifunction display.

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 15. 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 via the interior CAN to the electronic ignition lock control unit, which relays the request to the CDI control unit or ME-SFI control unit via the chassis CAN.
The CDI control unit or ME-SFI control unit then switches 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.





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