What to know about the Transmission Position Sensor (Switch):
Vehicles equipped with an automatic transmission are planned to start only in park or neutral gears. If a vehicle is able to start in reverse or drive gears, it can accidentally move, causing damage to property or injuries to occupants or bystanders. That’s why; automakers have developed a safety shutdown known as a transmission position sensor or range sensor that cuts the power to the starter control circuit if the vehicle is not in park or neutral. This sensor or switch is typically fixed on the side of the transmission and screws into the body of the transmission to detect in which gear the transmission is engaged. If the driver tries to start the vehicle when the transmission is engaged in a gear other than park or neutral, power is not distributed to the starter circuit. The vehicle will not crank, avoiding unintentional vehicle movement. If the transmission position sensor, or range sensor fails, the vehicle may be able to start while engaged in a drive gear.
SEE ALSO:WHAT IS SPEED SENSOR REPLACEMENT
Facts to Note:
Symptoms related to the transmission position sensor mimic those of other common problems.
Professional mechanics need to diagnose the symptoms for accurate repair.
The transmission position sensor is also commonly known as a transmission range sensor.
How to Fix:
The defective transmission position sensor switch is identified
The vehicle is lifted and held on jack stands
The faulty transmission position sensor switch is then detached
The new transmission position sensor switch is installed and the vehicle taken off the jack stands
The repair is confirmed and the vehicle is road tested for proper operation
While the transmission position sensor is does not require any routine service, as an electronic part, it can fail. If your automatic transmission-equipped vehicle is able to start in a gear other than park or neutral, or if your vehicle will not start when in park or neutral, you may need to change the transmission position sensor.
Common symptoms indicating you may need to change the Transmission Position Sensor (Switch)
Engine will not start at all
Engine will only start in neutral gear, not in park
Engine will start in engaged in drive or reverse gear
Importance of this service:
If your vehicle is able to start in gear, there is ability to cause injury to people or damage to property. If the range sensor fails, have it changed straightaway.