B303 Transmission Range Sensor
WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
B303 is a hall-effect sensor that has two signal circuits with inversely proportional PWM duty cycle outputs.
- Transmission Range Sensor is an input to the TCM, used to determine what transmission gear range the vehicle operator has selected and apply the clutches for that gear.
- Transmission Range Sensor is an input to the ECM, used to determine if the transmission is in park or neutral - for starter motor operation.