3 Series E46 325i (M54) TOUR
3 solenoid valves actuate the clutch actuator and the gearshift actuator for the gearshift movement.
1 solenoid valve actuates the S-Cam brake (S-Cam = bush with S contour) and the gearshift/selector
angle actuator for effecting a change of shift gate. At the same time, the solenoid valve serves as a
pressure relief valve for the hydraulic system.
The solenoid valves are only fed with current during the clutch actions and during gear changes.
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SMG control unit
The SMG control unit is the GS30 unit familiar from the E46. The SMG control unit takes the signals received
from the sensors and uses these to compute the actuation signals for the solenoid valves for clutch actions and
gear changes. Moreover, the SMG control unit sends information to various control units, e.g. to the engine
speed adjustment, to the program indicator and to the gear lever position indicator. [more ...]
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Reversing-light relay
The transmission position reverse gear signal is fed by the gearshift travel and selector angle sensors to the
SMG control unit. The SMG control unit generates the signal for the relay. The reversing-light relay is located in
the lid of the electronics box.
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Transmission
The SMG is based on the 6-speed manual transmission GS6-37BZ. The transmission housing has been
modified to hold the hydraulic unit with the actuators for clutch actions and gear change as well as additional
sensors. The gearshift detent and the selector detent on the selector shaft have been adapted. The construction
of the transmission and the clutch remain unchanged.
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Instrument cluster display
The selected drive positions and transmission programs, and the symbol for emergency program are shown in
3 segments in the instrument cluster. [more ...]
Additional measured variables from the following components:
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Brake-light switch
The brake-light switch signal is an analogue signal sent to the SMG control unit. For reasons of safety, the
brake-light switch signal is transmitted through the PT CAN (powertrain CAN) by the DME control unit (digital
engine electronics).
The brake-light switch signal is used for the following operations:
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To release the shift lever lock (shift-lock)
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To recognise a brake application
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To disengage a gear when the engine is switched off
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Starter inhibitor and electronic immobiliser EWS
The EWS only enables the starter motor if it receives the enable signal from the SMG control unit. The SMG
control unit recognises the wish to start via the terminal 50 input. The following conditions must be satisfied for
the start to be enabled:
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Gear lever position N must be engaged (the letter N must be shown in the instrument cluster display).
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The SMG control unit enables the start, the clutch is opened.
System functions
The SMG comprises the following functions:
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Engine start
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Gearshift
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Driving in cruise mode "C" (automatic mode)
SBT Sequential manual transmission SMG, based on GS6- 37BZ E46
BMW AG - TIS
14.02.2013 23:20
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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