? Gear retention when cornering ? Kick-down · The lateral acceleration sensor (integrated in

911 Transmission 3 ? Gear retention when cornering ? Kick-down The lateral acceleration sensor (integrated in If the accelerator pedal is depressed beyond the same component as the rotary speed the full-throttle pressure point (kick-down), sensor), which is located on the centre con- e.g. when overtaking, the transmission shifts sole and pro-vides the PSM system with in- down to the lowest possible gear and most formation, detects the lateral acceleration sporty shift map for the current vehicle and retains the respective gear depending on speed. This map is retained until the accel- the map and lateral acceleration. erator is released by more than 70%, and then the previous shift characteristics are resumed.? Downshifting when braking If the accelerator pedal is released quickly, ? Shift-up with overrun on slippery (icy) e.g. in a hazardous situation or when ap- road surfaces proaching curves (sporty driving style), and the brake is also actuated, the transmission In overrun conditions, especially in the low shifts down to the lowest possible gear for gears and on slippery road surfaces, the en- the vehicle speed. gine braking effect may cause slippage or The gear which is then activated remains locking of the rear wheels. engaged until the driver once again de- This driving condition is detected by the Tip- presses the accelerator pedal. tronic control unit which continuously com- This function allows the engine braking effect pares the speed of the rear wheels with the to be used. This also applies to downhill speed of the front wheels. If the speed of the driving. rear wheels is less than that of the front wheels, the transmission immediately shifts into a higher gear so that the speed of the rear wheels matches the speed of the front? Active gear skip into most sporty shift wheels and the hazardous driving situation map with locking rear wheels cannot occur. Whenever the vehicle is started, the trans- If the "PSM off" button is pressed, the func- mission control unit is set to the smoothest tion described above is also deactivated and and most economical shift map. can only be reactivated by pressing the but- In order to achieve the best possible accel- ton again or by switching the ignition off and eration (e.g. for an overtaking manoeuvre), then on again. the associated fast movement of the accel- On vehicles without PSM, switching off of this erator pedal is detected by the potentiometer function is not possible. and the transmission changes over to the more sporty and poweroriented shift map. If the accelerator pedal is now released by more than 25%, the previous shift charac- teristics are resumed. 2002 Service Information 3 -7