The functional range of the SZL can be divided into three main blocks:
In the steering column switch cluster, the following functions can be operated quickly and ergonomically by the driver:
The multifunction steering wheel (MFL) consists of
Located below the multi-function steering wheel are
The electronic control for the steering column switch cluster is divided into two electronic modules:
The signal transfer from the control elements in the multifunction steering wheel (MFL) is ensured by a coil spring.
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 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.
The gear selector lever involves the following functions
Function |
Operation |
|---|---|
Drive position D (Drive) |
Overpress downwards |
Drive position R (reverse gear) |
Overpress upwards |
Drive position N (neutral position): |
from drive position P: one-touch upwards or downwards from drive position D: one-touch upwards from drive position R: one-touch downwards |
Position P (park position) |
Touch lever inwards |
Information displayed to the driver
Transfer concept: When the driver operates the steering-column lever or the axial one-touch button, a message is sent to the EGS control unit (Electronic Gearbox Control).
Signal path: From SZL (steering column switch cluster) -> data bus BYTEFLIGHT -> SIM (Safety Information Module) -> data bus BYTEFLIGHT -> ZGM (Central Gateway Module) -> data bus PT-CAN -> EGS (Electronic Gearbox Control).
For reasons of safety, there is also a serial line between the SZL and EGS. The same messages are transmitted across this line as across the 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 unlock: In an emergency, the electronic parking lock be unlocked mechanically:
The steering-column lever for cruise control increases or reduces the travelling speed.
The cruise-control system comes with the special equipment ”ACC, Adaptive Cruise Control”.
Function |
Operation without ACC |
Operation with ACC |
Switch from OFF to ON and set the current speed. If the cruise control is already switched on, the set speed is increased/reduced. |
One-touch forwards/backwards |
One-touch forwards/backwards |
Switch from OFF to cruise control ON and set the current speed. If the cruise control is already switched on, the next higher/lower stored speed stage is activated. |
Overpress forwards/backwards |
|
Calls up stored speed |
Touch lever inwards |
Touch lever inwards |
Sets or deletes speed stage |
Touch lever inwards (long - at least 3 seconds) |
|
Switches off the cruise control |
Touching lever up/down |
Touching lever up/down |
Changes distance setting (only with ACC) |
|
Operate rotary actuator |
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. frequently required speeds, such as 30 km/h, 50 km/h, 60 km/h. For these required speeds, speed marks can be set and stored.
Programming required speeds: It is best to program required speeds with the vehicle stationary! Reason: when the vehicle is moving, the speed entered as required speed is set immediately!
Deleting required speed:
Transfer concept: when the driver operates the steering-column lever, the axial one-touch button or the rotary actuator (in the case of ”ACC, Adaptive Cruise Control” as special equipment), a message is sent to the DME/DDE or the ACC control unit.
Signal path: From SZL (steering column switch cluster) -> data bus BYTEFLIGHT -> SIM (Safety Information Module) -> data bus BYTEFLIGHT -> ZGM (Central Gateway Module) -> data bus PT-CAN -> DME/DDE or ACC.
Operating the Steptronic button causes the EGS (Electronic Gearbox Control) to shift gear upwards or downwards.
The Steptronic buttons are redundant for safety reasons redundant, 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 field 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 reasons of safety, there is also a redundant serial line between the SZL and EGS.
The function keys to the right are keys for the choice of various functions:
The following control units are involved in the message transmission for the SZL:
For safety reasons, there are two serial cable connections in addition to the bus connection:
For all work on the steering column switch cluster, comply with the safety legislation for work on airbags!
Disconnect battery!
In an emergency, the electronic parking lock be unlocked mechanically: Undo the cover in the footwell on the driver's side at the left-hand A-pillar.
In the USA, the cover can only be removed with the identifier. This ensures that unauthorised persons are unable to release the electronic parking lock manually.