The longitudinal-acceleration sensor is required for the uphill/downhill detection and braking deceleration functions.
An additional function is uphill driving detection. If a gradient value stored in the control unit is exceeded when driving up a hill, driving off in 2nd gear is not possible.
The longitudinal-acceleration sensor B49 is installed beneath the passenger seat. The longitudinal-acceleration sensor is a Piezo acceleration sensor. The sensor is supplied by the control unit with +5V and ground.
Over the feedback wire, approx. 1.8V is at the sequential M-gearbox control unit in idle state. With longitudinal acceleration, the resistance in the sensor changes and thus the voltage on the feedback wire. With increasing longitudinal acceleration, the level of voltage rises.
The lateral-acceleration sensor is required in the sequential M-gearbox control unit for the cornering function in the A program. The cornering function prevents gearshifts that would lead to unstable vehicle handling. The control unit sending across the CAN data line is the DSC control unit (Dynamic Stability Control).
The lateral-acceleration sensor is used primarily as an input signal for the DSC as a measured variable for the target yaw rate. The target yaw rate corresponds to cornering which is still stable under the given driving conditions on reaching the cornering limit speed.
The transverse acceleration sensor is installed in the left-hand A-pillar. The lateral-acceleration sensor is a Piezo acceleration sensor. The sensor is supplied by the control unit with +5V and ground.
Over the feedback wire, approx. 1.8V is at the sequential M-gearbox control unit in idle state. With lateral acceleration, the resistance in the sensor changes and thus the voltage on the feedback wire. With increasing lateral acceleration, the level of voltage rises.