ECU - The Brain Of A Machine

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What is an ECU?

An electronic control unit (ECU) is a small device in a vehicle’s body that is responsible for controlling a specific function. 

Today’s vehicles may contain 100 ECUs or more, controlling functions that range from the essential (such as engine and power steering control) to comfort (such as power windows, seats, and HVAC), to security and access (such as door locks and keyless entry). ECUs also control passive safety features, such as airbags, and even basic active safety features, such as automatic emergency braking.

Each ECU typically contains a dedicated chip that runs its software or firmware and requires power and data connections to operate. 

Quite simply put ECU is a device that controls all the electronic features in a car. This may range from fuel injection to maintaining perfect cabin temperature to controlling braking and suspension. Some vehicles have multiple ECU controlling different features while some have a single one controlling everything.


How Does an ECU Work?

Working in an ECU is not complicated as one might assume. It is an electronic device that has base numbers and parameters filled in its memory. With multiple sensors around a vehicle feeding the ECU data, it can manage and control the electronic systems efficiently by giving orders to improve their output.

An ECU receives inputs from different parts of the vehicle, depending on its function. For example, a door lock ECU would receive input when a passenger pushes the door lock/unlock button on a car door or a wireless key fob. An airbag ECU would receive inputs from crash sensors and from sensors that detect when someone is sitting in a particular seat. And an automatic emergency braking ECU would receive inputs from forward-facing radars that detect when the vehicle is approaching an obstacle too quickly.

The ECU would then communicate to actuators to perform an action based on the inputs. In our examples, the door lock ECU would activate an actuator that locks or unlocks the corresponding door. The airbag ECU would choose which airbags to deploy, depending on the location of the passengers, and then direct the actuators to deploy them. And the automatic emergency braking ECU would engage the brakes to prevent a collision.


5 Types of ECU

With vehicles having multiple ECU they are divided on what tasks they perform. Some of these types are as follows.


Engine Control Module

With its sensors, the ECM ensures the amount of fuel and ignition timing necessary to get the most power and economy out of the engine.


Brake Control Module

Used in vehicles with ABS, the BCM makes sure that the wheels are not skidding and determine when to trigger braking and let go of the brake to ensure the wheels don’t lock up.


Transmission Control Module

Used on an automatic vehicle, the TCM ensures you get the smoothest shifts possible by assessing the engine RPM and acceleration of the car.


Telematic Control Module

Another one with the same abbreviation this TCU ensures the car onboard services are up and running. It controls the satellite navigation and Internet and phone connectivity of the vehicle.


Suspension Control Module

Present in Cars with active suspension systems, the SCM ensures the correct ride height and optimal changes to suspension depending on the driving condition.


How to Choose an ECU that Matches Your Machine?

First, you need to provide us with your engine nameplate number and genie model. As we all know, the ECU needs to determine the programming, so it is necessary to determine the model of the machine, use the model to match the ECU, and then set the programming. In this way, you can get the ECU that fits your machine.


What happens If An ECU Is Faulty?

A faulty ECU is probably the worst thing for a car. It’ll work but its performance will be heavily affected. You’ll notice sudden drops in fuel economy and jerky gear shifts. The check engine light staying on might mean a lot of possible errors but an ECU fault is one of the major ones.


How much does an ECU replacement cost?

This will vary depending on a variety of factors, such as the type of ECU and the make and model of the vehicle. If you get it done by a mechanic in the UK, the price of an engine ECU replacement typically ranges from £150 to £500 plus labor costs. It’s possible to buy an electronic control unit at a lower price online, although you should keep in mind that it is a complex device that may require professional tuning. 



ECU plays a vital role and contains complex programs, so if you need to purchase or replace your ECU, we will provide you with professional guidance and help you complete the programming you are adapted to. has the answers you're looking for – and the products, too! 


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