Mechanical reasons:
* Worn or damaged shift mechanism
* Shift mechanism contaminated with dirt, oil or debris
* Worn or damaged sensor rod
* Incorrect shift cable adjustment
Electrical reasons:
* Loose or damaged electrical connections
*Damaged or broken wires
* Malfunction of the electronic control unit (ECU) of the automatic transmission
* Malfunction of the selector position sensor itself
Other reasons:
*Low ATF (transmission fluid) level
*General poor condition of gearbox
* Problems with the automatic transmission control module (TCM)
Notes:
* A faulty shift position sensor can lead to a variety of automatic transmission problems, including:
*Shifting gears at the wrong time
* Inability to change gears
*Hard gear shifting
*ATF leaks
* Accurately diagnosing the cause of a faulty shift position sensor usually requires a comprehensive inspection by a qualified mechanic.