The output speed sensor is a crucial component in a vehicle’s transmission system. It is responsible for monitoring the rotational speed of the transmission output shaft, which is then used by the transmission control module to determine the appropriate gear ratio for the vehicle.
When the output speed sensor fails or experiences a malfunction, it can cause the transmission control module to receive incorrect information, leading to a variety of transmission issues. The most common symptom of a faulty output speed sensor is a malfunction indicator light (MIL) on the dashboard, accompanied by shifting problems, such as slipping gears or delayed shifts.
The output speed sensor is typically located on the transmission’s tail shaft and consists of a magnetic pickup and an electronic circuit board. The magnetic pickup, which is attached to the transmission’s output shaft, generates a small electrical current as it rotates. This current is then sent to the electronic circuit board, which converts the signal into a digital signal and sends it to the transmission control module.
When the output speed sensor circuit experiences a malfunction, it can be caused by a variety of factors. Some common causes include a faulty magnetic pickup, damaged wiring or connectors, and a faulty electronic circuit board.
To diagnose the issue, a technician will typically use a diagnostic scan tool to retrieve any diagnostic trouble codes (DTCs) stored in the transmission control module. The most common DTC for an output speed sensor malfunction is P0720, which indicates a problem with the output speed sensor circuit.
Once the issue has been diagnosed, the faulty component must be repaired or replaced. If the magnetic pickup is damaged or faulty, it will need to be replaced. If the wiring or connectors are damaged, they will need to be repaired or replaced. And if the electronic circuit board is faulty, it will need to be replaced.
It is important to have a faulty output speed sensor circuit repaired as soon as possible, as it can lead to further transmission problems if left unaddressed. In some cases, a faulty output speed sensor can even cause damage to other components in the transmission system, leading to costly repairs.