What Is a Transmission Shift Sensor?

Transmission shift sensors are a piece in a car's engine that gauges the status of the transmission and relays this information to the transmission control module. Based on how the shift sensor outputs, the automatic transmission system determines whether or not to shift gears.

The transmission shift sensor is an integral part of the automatic transmission system in any transmission solenoid. A transmission solenoid uses hydraulic valves controlled by a microprocessor to change gears. The sensor itself converts transmission activity into an electronic signal, which is then fed into the microprocessor. The microprocessor compares the sensor's report with a model of ideal conditions for a gear shift. Based on the difference between the microprocessor's model and the sensor report, the processor decides whether or not to engage the hydraulic valves and shift gears. Meanwhile, the sensor takes another report on the transmission's conditions, restarting the process. This feedback loop forms the foundation for an automatic transmission system.

One of the most important tasks of an automatic transmission shift sensor is the initial start. Modern cars do not activate the starter motor unless the shift sensor reports that the car is parked. If the sensor is unable to tell if the car is in park, it prevents the starter motor from running, resulting in an inoperable vehicle.