Shifting Using Geartronic
When the gear selector is moved to the Geartronic position (MAN) the automatic transmission remains in hydraulic position D, but 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 the MAN position. A signal is sent to the gear selector module (GSM) to light the M LED and switches off the other LEDs. The transmission control module (TCM) determines if shifting can be carried out and the driver information module (DIM) indicates the current gear. If shifting is permitted the solenoids are activated according to each specific gear pattern.
However, in certain situations the transmission control module (TCM) assumes the shifting decision. The following 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
- Automatic down shifting occurs 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 then, exceeds 25 km/h. in other cases 2nd gear is retained. For example, when 3rd gear is engaged despite the car being stationary
- Manual up shifting is required after automatic down shifting. Kick-down is not available in the Geartronic-position (MAN)
- The permitted speed for manual down shifting corresponds to those for kick-down downshifting, i.e. engine speed at approximately 6,000 RPM
- If the transmission temperature becomes too high the transmission control module (TCM) determines the shift position. The purpose is to maintain a gear where lock-up is possible at the current speed
- Lock-up is possible in 3rd, 4th and 5th gears. (1st and 2nd gears do not have lock-up).
Other
In position MAN the lever position signal to the gear selector module (GSM) is generated as follows:
For each of the three gear selector positions a hall sensor is mounted on the printed circuit board for the gear selector control module (GSM). A permanent magnet on the 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.