Transmission Selector Lever
The new automatic transmission for the E65 has an electronic gear shift system. That means there is no mechanical link between the selector lever and the gearbox.
The transmission selector lever is positioned on the right-hand side of the steering column and like the turn signal switch, is a momentary switch.
The selector lever is used to select the transmission modes R - N - D and P.
Advantages of electronic gear shift system:
- Greater ease of operation, e.g. the parking lock is engaged automatically when the key is removed from the ignition.
- The components of an electronic gear shift system take up less space.
- No transmission of noise or vibration as there is no physical connection between lever and gearbox.
- Electronic shift lock prevents unauthorized operation. This means that the steering lock is no longer required as an anti-theft feature.
The transmission selector lever is the main input device for controlling the electronic transmission control unit (EGS).
The selector lever has 7 Hall-effect sensors that are duplicate-coded in such a way that the failure of one of sensors does not result in failure of the complete selector lever.
The driver's request is detected by the dual-system sensors in the transmission selector lever and transmitted by the SZL to the electronic transmission control unit (EGS).
The EGS checks that the gear shift is permissible and initiates the operation via the electronic- hydraulic control unit that is integrated in the automatic gearbox.
The currently selected gear and any Check Control messages such as "Press brake pedal to engage gear" are displayed on the instrument cluster for the information of the driver.
The selector lever signals are not carried out unless the EGS has received a clearance signal from the Car Access System (CAS). That means that an authorized key must have been detected in the holder unit of the ignition switch. If the key is removed from the ignition, the parking lock is automatically engaged.
The gear shift "gate" pattern on the selector lever is fitted with locator lighting (controlled by terminal 58g).
When the selector lever is operated, the signal is transmitted to the SZL.
From the SZL the signal is passed to the byteflight bus.
It then travels via the SIM and the ZGM to the PT-CAN and ultimately the electronic transmission control unit (EGS) where it is processed.
For safety reasons, there is a serial cable available as redundant back-up in case of any bus problems.