Check that the sensor output voltage at pin 2 is between 0.3 and 4.7 V (pins 4 and 5).Check that the power supply at pin 3 is between 4.7 and 5.3 V.Check that there is earth at pin 1.Longitudinal acceleration sensor pin outPin 1 - EarthPin 2 - SignalPin 3 - 5 V power supply