The functions of the steering column control centre can be subdivided into three main blocks:
The multi-function steering wheel provides the means by which the driver can easily and ergonomically perform the following functions:
The multi-function steering wheel consists of
Located below the multi-function steering wheel are
The electronic control system for the steering column control centre and the multi-function steering wheel is divided into two electronic modules:
Signal transmission from the steering wheel module to the steering column module is effected by means of a coil-spring conductor.
The turn indicator-low beam switch consists of
The turn signal/dip switch also incorporates two axial touch switches .
Transfer concept: steering column stalks and axial touch buttons have differing signal transmission routes:
Steering column stalk signal transmission route: When the driver operates the steering column lever, a message is sent to the light module. Signal path: from steering column switch centre -> data bus BYTEFLIGHT -> Safety and Information Module -> data bus BYTEFLIGHT -> Central gateway module -> data bus K-CAN SYSTEM -> light module.
For safety reasons, there is an additional serial cable from the steering column switch centre to the light module. An analogue coded signal is applied to that cable and is analysed by the light module. Each switch position is allocated a voltage range. The serial cable enables transmission of all positions of the turn signal/dip switch in the event of a bus fault, though with some limitations to the possible functions:
Touch button signal transmission path: When the driver operates one of the axial touch buttons, a message is sent to the instrument cluster.
Signal path: from steering column switch centre -> data bus BYTEFLIGHT -> Safety and Information Module -> data bus BYTEFLIGHT -> Central gateway module -> data bus K-CAN SYSTEM -> instrument cluster.
The lever for the cruise-control system consists of
Speed marks of required speeds: the steering-column lever for cruise control can also be used to select required speeds. Required speeds are e.g. frequent speeds used, such as 30 km/h, 50 km/h, 60 km/h. Speed marks can be set and stored for these required speeds.
The preset cruise control speeds are car & key memory functions, i.e. they can be set and stored individually for each driver.
Transfer concept: When the driver operates the steering-column lever or the axial one-touch button, a message is sent to the digital engine electronics.
Signal path: from steering column switch centre -> data bus BYTEFLIGHT -> Safety and Information Module -> data bus BYTEFLIGHT -> Central gateway module -> data bus PT-CAN -> digital engine electronics.
Transfer concept: When the driver operates the knurled wheel (not RR01), a message is sent to the active cruise control (ACC) control unit.
Signal path: from steering column switch centre -> data bus BYTEFLIGHT -> Safety and Information Module -> data bus BYTEFLIGHT -> Central gateway module -> data bus PT-CAN -> active cruise control (ACC).
The gear selector lever is used for fully electronic selection of the gear positions R - N - D and P (reverse gear - neutral position - drive - park position). The gear selector lever consists of
The desired drive position is registered by seven Hall sensors. The Hall sensor are configured in such a way that if an individual Hall sensor fails the operability of the gear selector lever is retained.
Transfer concept: When the driver operates the steering-column lever or the axial one-touch button, a message is sent to the Electronic Gearbox Control.
Signal path: from steering column switch centre -> data bus BYTEFLIGHT -> Safety and Information Module -> data bus BYTEFLIGHT -> Central gateway module -> data bus PT-CAN -> Electronic Gearbox Control.
For safety reasons, there is a serial cable from the steering column switch centre to the electronic gearbox control. The same messages are transferred on this cable as across the data buses.
Electronic parking lock: with electronic gearbox control, the steering column lock can be eliminated as an antitheft measure: the electronic parking lock replaces the steering column lock.
Electronic parking lock ”emergency” release: in an emergency, the electronic parking lock be unlocked mechanically:
The wiper switch consists of:
At ”ignition off”, the wiper and the rain/light sensor are switched off.
Transfer concept: When the driver operates the steering column lever for the windscreen wipers, a message is sent to the wiper module.
When the driver operates the axial button or the knurled wheel (not RR01),
Signal path: from steering column switch centre -> data bus BYTEFLIGHT -> Safety and Information Module -> data bus BYTEFLIGHT -> Central gateway module -> data bus K-CAN SYSTEM-> wiper module or rain/light sensor.
Operating the Steptronic button causes the electronic gearbox control to shift gear upwards or downwards.
The Steptronic buttons are redundant for safety reasons, one each to the left and right on the multi-function steering wheel.
The Steptronic buttons are only enabled when the S/M key (S = Sport program, M = Manual shift program) on the right of the multi-function steering wheel has been switched to Manual: an M is displayed in the program display of the instrument cluster (display area between speedometer and revolution counter). Depending on the gear selection, M1 to M6 appears for the current gear.
The Steptronic buttons are Hall sensors.
For safety reasons, there is a redundant serial cable from the steering column switch centre to the electronic gearbox control.
The function buttons enable selection of
The steering wheel is adjusted by means of the button on the side of the steering column trim.
The fanfare horns serve both as a warning signal and as redundant-system audible alarms of the vehicle.
The directly read horn switch signal is sent as a valid status via the steering wheel module and the coil spring conductor to the steering column module (steering column control centre module). The steering column module can control the high-tone and low-tone horns separately. The power consumption for each horn is approx. 5 A.
The steering wheel heating system consists of
The steering column control centre activates the heater coil as required in order to ensure even heating of the steering wheel.
In all cases, only perform work on the fuel pump with the ignition off!
All work on the airbags must be carried out with the battery disconnected!
Connect and disconnect all BYTEFLIGHT control units, sensors and generators only with the battery disconnected!
If a fibre-optic cable on the BYTEFLIGHT bus has to be repaired, it must be borne in mind that there may only be one join between the Safety and Information Module and a satellite. For this reason, no repairs may be performed on the fibre-optic cable between the Safety and Information Module and the the door satellites, as there is already a join with the door connector. In the case of a defect, the fibre-optic cable must be replaced!