The automatic transmission position sensor (automatic transmission) is a device that determines the position of the gearbox selector. It transmits information about the selected gear to the transmission’s electronic control unit (ECU). The operation of the automatic transmission position sensor is based on the following principles:
Working principle:
The automatic transmission position sensor is usually a multi-contact switch connected to the gear selector. It has a number of contacts, each of which corresponds to a specific switching position:
*Parking (P)
* Neutral (N)
* Reverse (R)
* Drive (D)
* Auxiliary gear (S or L), etc.
When changing gears:
When the driver changes gearbox mode, the gear selector moves and so does the position sensor. The contact corresponding to the selected gear closes.
Electrical signal:
The closed contact of the sensor transmits an electrical signal to the transmission ECU. The ECU interprets the signal to determine the selected gear.
Control of automatic transmission functions:
Information about the selected gear is used by the ECU to control various automatic transmission functions, such as:
* Gear shift
* Torque converter lock
* Enable cruise control
* Execute parking mode
*Display gear position on dashboard
Types of automatic transmission position sensors:
There are several types of automatic transmission position sensors, including:
* Mechanical: Controlled by physical movement of the gear selector.
* Electronic: Uses electronic signals to determine gear position.
* Integrated: Integrated into the gear selector, providing compactness and reliability.
Malfunctions of the automatic transmission position sensor:
A faulty automatic transmission position sensor can lead to improper operation of the gearbox, for example:
* Inaccurate gear position display
* Inability to change gears
* Sudden gear changes without driver command
*Transmission fluid leak (in some cases)
If the automatic transmission position sensor malfunctions, the malfunction indicator on the dashboard usually lights up and requires diagnosis and repair.