Automatic transmission speed sensor
The automatic transmission (automatic transmission) speed sensor measures the rotation speed of the transmission output shaft. The speed (RPM) transmitted by the sensor is used by the engine management system (ECU) to:
* Adjustment of ignition timing and fuel supply
* Torque converter lockup control
* Display speed information on the instrument panel
* Diagnosis of transmission faults
Types of automatic transmission speed sensors
There are two main types of automatic transmission speed sensors:
* Inductive sensors: Use electromagnetic induction to generate an electrical signal that is proportional to the speed of rotation.
* Hall effect sensors: Use the Hall effect to generate an electrical signal that corresponds to specific points on the transmission shaft.
Location of the automatic transmission speed sensor
The automatic transmission speed sensor is usually located on the transmission output shaft or on the transmission housing. It can be secured with screws or bolts.
Automatic transmission speed sensor malfunctions
Malfunctions of the automatic transmission speed sensor can lead to the following problems:
* Incorrect speed readings on the instrument panel
* Jerking or slipping of the transmission
* Slipping at low speeds
* Deteriorating fuel economy
* Setting trouble codes (DTC)
Diagnostics of automatic transmission speed sensor faults
Malfunctions of the automatic transmission speed sensor can be diagnosed as follows:
* Checking trouble codes (DTC) using OBD2 scanner
* Measuring the voltage or frequency of the signal on the automatic transmission speed sensor using a multimeter
* Checking the integrity of wiring and connections
Replacing the automatic transmission speed sensor
Replacing an automatic transmission speed sensor is usually performed by a mechanic. To do this you need:
* Remove transmission pan
* Unscrew and remove the old speed sensor
* Install a new speed sensor
* Install transmission pan
* Replace transmission fluid