On the Peugeot 306, the speed sensor is located in the gearbox (under the gearbox casing) or on the rear of the gearbox.
To remove the speed sensor:
1. Place the car on a level surface.
2. Turn off the engine.
3. Disconnect the battery negative cable.
4. Raise the car and secure it on safety stands.
5. Locate the speed sensor.
6. Remove the bolt or screws that hold the sensor in place.
7. Pull the sensor out of the gearbox.
To install the new speed sensor:
1. Insert the new sensor into the gearbox.
2. Secure the sensor with the bolt or screws.
3. Connect the battery negative cable.
4. Lower the car and remove the safety stands.
5. Start the engine and test the speedometer.
