Location of automatic transmission speed sensor on Nissan X-Trail T31
1. Located on the automatic transmission housing under the front wheel drive shaft.
2. Connected to the automatic transmission housing with two bolts.
3. Has an electrical connector with three wires.
Electrical circuit of the automatic transmission speed sensor
| Wire color | Destination |
|—|—|
| Black | Earth |
| Red | Supply voltage (12 V) |
| Blue | Sensor output |
Operating principle of the automatic transmission speed sensor
1. The sensor is a pulse generator that produces an electrical signal.
2. The pulse frequency is proportional to the rotation speed of the front wheel drive shaft.
3. The electrical signal is sent to the electronic control unit (ECU) of the automatic transmission.
4. The ECU uses the speed sensor signal to detect vehicle speed and control gear shifting.
Automatic transmission speed sensor malfunctions
* Faulty output signal: May cause improper shifting and vehicle handling problems.
* No signal: The automatic transmission may go into emergency mode and will not shift gears.
*Short circuit: May cause damage to the automatic transmission ECU or other electronic components.
Replacing the automatic transmission speed sensor
1. Disconnect the negative terminal of the battery.
2. Remove the protective cover under the vehicle.
3. Disconnect the electrical connector of the automatic transmission speed sensor.
4. Unscrew the two bolts securing the sensor to the automatic transmission housing.
5. Remove the old sensor and install the new one.
6. Tighten the mounting bolts.
7. Connect the electrical connector.
8. Reinstall the protective cover.
9. Connect the negative terminal of the battery.
10. Clear trouble codes using the diagnostic scanner.