Toyota automatic transmission speed sensor
Purpose:
The Transmission Speed Sensor (TSS) measures the rotation speed of the transmission output shaft. The data is sent to the transmission control module (TCM), which uses it to adjust the operation of the automatic transmission.
Location:
The location of the sensor depends on the Toyota vehicle model. Often it is located:
* On the automatic transmission housing
*On the transmission output shaft
*Inside transmission
Design:
The sensor is a device that generates an electrical pulse with each revolution of the output shaft. It consists of:
* Electromagnetic coil
* Gear or magnet attached to the output shaft
Working principle:
As the output shaft rotates, a gear or magnet passes by an electromagnetic coil, creating a change in the magnetic field. This generates an electrical pulse whose frequency is proportional to the speed of rotation of the shaft.
Sensor types:
Toyota cars use two main types of automatic transmission speed sensors:
* Inductive sensor: uses an electromagnetic coil to measure changes in the magnetic field.
* Hall Effect Sensor: Uses the Hall effect to detect the movement of a magnet.
Signs of malfunction:
*Hard shifting
*Transmission slippage
* Vibration when shifting gears
* ‘Check Engine’ light on
Diagnostics and replacement:
To diagnose a faulty automatic transmission speed sensor, a fault code scanner (OBD2) or a special diagnostic tester is required. If the sensor is faulty, it must be replaced. Replacing the sensor usually requires special tools and knowledge.