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Home >> Mercedes Benz >> 2012 >> E 63 AMG Wagon (212.274) V8-5.5L Turbo (157.981) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Antitheft and Alarm Systems >> Keyless Entry >> Description and Operation >> GF80.61-P-3012FL Engine Start/Stop, Function

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



GF80.61-P-3012FL 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
The function engine start/stop enables to engine to be started and switched off via the KEYLESS-GO start/stop button (S2/3).

The engine start/stop function comprises the following subfunctions.
^ Function sequence for interrogation of 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 interrogation of transmitter key
If a door is opened and closed again, the electronic ignition lock control unit (N73) causes an interrogation of the transmitter key by the KEYLESS-GO transmitter key during the starting off process (v > 0 km/h) (N69/5).
The transmitter key is only interrogated after the last door has been closed.
If the vehicle stops and no door is opened, no new interrogation takes place as well.

If during the interrogation of the transmitter key no transmitter key is detected in the vehicle interior, the IC issues the message "Key not detected" in red text. 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 module control unit (N15/5) (on transmission 722.6) or intelligent servo module for DIRECT SELECT (A80) (on transmission 722.9) transmits the status "Gear selector lever in place P or N" over 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 passes on the status "Transmission in position P or N" via the body CAN (CAN B) to the KEYLESS-GO control unit.

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 this via the body CAN to the KEYLESS-GO control unit.

The KEYLESS-GO control unit then transmits wake-up and location finding signals via the following components to the transmitter key:
- 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)

The transmitter key transmits its access authorization code and position to the FM 1, AM, ZV and KEYLESS-GO antenna amplifier (A2/18), which relays the data to the KEYLESS-GO control unit. 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 this is defined as valid and the transmitter key is in the vehicle interior, it switches the corresponding circuits (circuit 15) and the engine is started via the CDI control unit or ME-SFI control unit.

Function sequence for display of fault messages

The following situations lead to output of fault messages:
- If during a start attempt no transmitter key is detected in the vehicle interior, the IC (A1) issues the message "Key not detected". The start attempt is not started. The status of the circuit remains unchanged.
- If, during a start attempt, the transmission is not in place "P" or "N", an acoustic warning tone sounds and a corresponding message is output to the instrument cluster.

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 reads in the KEYLESS-GO start/stop button directly and transmits the circuit status "circuit 15 OFF" via the body CAN to the KEYLESS-GO control unit.
The KEYLESS-GO control unit transmits the request to switch off via the body CAN to the electronic ignition lock control unit, which passes on the request via the chassis CAN to the CDI control unit or to the ME-SFI control unit.
As a result of this the CDI control unit or the ME-SFI control unit ME switches off the engine depending on the vehicle speed.

Switching off the 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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