The supervision of the operation of the automatic transmission in cars is carried out by means of a transmission controller. This is a device that optimises the settings of the transmission. The controller receives signals from a number of sensors in different parts of the car in order to match the gears to the speed and engine speed, and thus optimise fuel consumption. With the gearbox controller, the settings are matched in real time to the conditions in which the car is being used.

What is an indication of a malfunctioning gearbox control unit?

The gearbox controller is a rather complex device with many electronic parts that can fail over time. This can be felt when changing gears, e.g. there will be some characteristic jerking. Over time, the malfunctions can become more apparent and may end up with the gearbox locking up completely. If the controller malfunctions, it may supply the wrong amount of oil to the transmission. If the communication with the sensor is interrupted, a malfunction will also occur. Failure of the automatic transmission controller can be dangerous for both the driver and passengers.

If you suspect damage to the controller, it is worth contacting a diagnostic station to decide on repairs. The controller is a device largely composed of electronics so not every mechanic will know how to correctly diagnose the fault and remove the irregularities. Often, mechanics will suggest replacing the entire controller and in the case of many car models you can also purchase replacements, which will be much cheaper than the original controller from an authorised garage.

A new gearbox controller for many car models is an expense of between €500 and €1,000, while a professionally refurbished controller will usually cost between €200 and €400. You can purchase these at Cost of replacing the gearbox control unit Here you can find transmission controllers for Volkswagen, Mercedes, Audi, BMW, Renault, Citroen and many other cars. Choosing a remanufactured controller is a very good idea for people who are looking for savings as well as want to have the repairs made quickly; in some cases it can take up to a few weeks to import a controller from the manufacturer.