GEARSHIFTING With GEARTRONIC
When the gear selector is moved to the Geartronic position the automatic transmission remains in hydraulic position. When the gear selector is moved upwards (+) the gear selector module (GSM) transmits a signal to the transmission control module (TCM) to shift up. When the gear selector is moved downwards (-), a signal is transmitted to the transmission control module (TCM) to shift down. The driver information module (DIM) switches the symbol in the combined instrument panel from D to the current gear, for example 3, when the gear selector is in M mode. The transmission control module (TCM) transmits a signal to the gear selector module to light the M LED and switch off the other LEDs. The transmission control module determines if the shift can take place. If shifting is permitted the solenoids are activated according to each specific gear pattern.
However, in certain situations the transmission control module takes over responsibility for determining shifting. The follow applies:
- When stationary only 1st, 2nd and 3rd gears can be selected. 4th gear can be selected at speeds in excess 30 km/h and 5th at speeds in excess of 40 km/h
- The kick down function is only available in the position.
- Automatic down shifting occurs for all gears below a certain speed. Example: 2nd gear is selected. Automatic down shifting occurs when shifting from 2nd gear to 1st at 2 km/h if the speed, before this, has exceeded 25 km/h. Otherwise 2nd gear is maintained. For example, there may be situations when 2nd or 3rd gear is engaged despite the car being stationary. Manual up shifting is required after automatic down shifting
- The permitted engine speeds for manual down shifting corresponds to those for kick-down up shifting, i. e. engine speeds of approximately 6, 000 RPM
- If transmission temperature becomes too high then the Transmission Control Module takes over the gearshift decisions. The purpose of this is to engage a gear where lock-up is possible at the current speed.
- Lock-up is possible in 3rd, 4th and 5th gears..
Other
In position M, the signal indicating the position of the lever to the gear selector module is generated as follows: For each of the three gear selector positions there is a Hall sensor on the printed circuit board for the gear selector control module. A permanent magnet on the cover in the gear selector lever affects the output signals from the sensors to the control module. The control module can read off the position of the lever through the differences in the signal characteristics.