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What Is Electronic Control Unit (ECU) in Vehicle And How Does It Work

Just like you need a central motherboard to control all the computer components, you need an electronic control unit in a car that can control all the electronic components inside your car. In this article, you’ll go through all the essential details related to a vehicle’s electronic control unit.

Table of Contents

What’s An Electronic Control Unit In A Vehicle?

In every car, you’ll find some electronic components like windshield wipers, power windows, headlights, taillights, etc. So how are they controlled? When you press the button to open or close your power windows, there’s an electronic system working behind your input, that rolls the
window glass up or down. That’s possible with the help of an ECU.

An ECU is the central control system in a car that governs all the electronic components. An ECU makes sure that your wipers work according to your set speed, headlights throw low beam or high beam, depending on what button you pressed, etc.

What’s The Use Of An ECU?

  • ECU Helps In Engine Performance Optimization
    Your car’s ECU can take care of perfect fuel injection timing, ignition, air-fuel mixture, etc., to improve the overall engine performance. In addition to that, you’ll also notice a car with a good ECU will emit less carbon.
  • It Facilitates Improved Security Systems
    Think of any security system in your car like airbags, ABS, traction control, electronic stability, etc., they all work just because of an ECU in the car. An ECU takes charge of these systems and makes sure that the security systems work in the desired way.

What’s Inside An ECU?

Components can be found in ECU
Components can be found in ECU
  • Microprocessor
    Even an electronic control unit has a central processing system, that’s called its microprocessor. It processes all the received inputs from the user and assigns the tasks to the concerned part(s)s of the car.
  • Memory
    Even a car’s electronic control unit has RAM and ROM. ROM is needed for installing the firmware and any other software that the ECU hardware may need to drive the entire system. RAM is, of course, needed as a physical memory to save on-going threads’ calculations and cached values.
  • Analog to Digital Converter
    This converter translates all the analog signals received from the sensors and sends them to the microprocessor for processing.

Also read: Microcontroller VS Microprocessor – Unveiling the powerhouses of the digital world

What Are the Types Of ECUs?

  • Engine Control Unit
    This type of electronic control unit takes care of the engine’s functionalities like fuel injection, etc.
    The anti-lock braking system is also controlled by an electronic control unit, that’s one of the most common types of ECUs in the picture nowadays.
  • Airbag Control Unit
    Since most cars nowadays have mandatory airbags installed in them, an ECU is needed for ensuring smooth functioning of those airbags.
  • Infotainment Control Unit
    This type of electronic control unit is in charge of the entire infotainment system, that includes speakers, touchscreen, and other multimedia systems, including charging sockets.
Something about electronic control unit

How Does An Electronic Control Unit Work?

1.There are several sensors installed in the car. So, for example, when you press the window glass down button, the sensor under the button will receive the signals.
2.The received signals are forwarded to the analog to digital converter, and after the conversion, the digital signals are forwarded to the microprocessor.
3.The microprocessor will process what signal was sent, which sensor sent the signals, and what’s the destination of the signals.
4.After processing, the microprocessor will instruct the concerned part of the car, i.e. the windows to roll up or down, based on your input.
5.The windows will keep rolling down for the time period when you’ve kept the button pushed. By keeping the button pushed, you’re triggering the sensors continuously to keep sending the data to the ECU.

Comparing Mechanical Controls VS Electronic Control

  1. Physical Link
    ●The mechanical system has a physical link between the controls and the part that needs to be controlled.
    ●The electronic system has a circuit of sensors, wires, controls, and the parts that need to be controlled, requiring reduced space in the car.
  2. Design Simplicity
    ●Mechanical systems are simpler in design as compared to ECU.
    ●ECU demands a higher level of skills and engineering to design ECU, as the designs are rather complex.
  3. Output & Features
    ●Mechanical systems have limited exposure to what a car maker can do with the cars. Mechanical systems don’t allow making highly advanced features like better engine performance, etc.
    ●An electronic control unit or electronic systems help in achieving modern and better output and features in a car that you cannot expect from a mechanical system. Use of sensors to achieve automation ain’t possible in mechanical systems but is possible in electronic systems.

When Does An ECU Fail?

Factors that cause electronic control unit failure
Factors that cause electronic control unit failure

1.Extreme temperature: When the sensors and wires are exposed to high temperature, the entire ECU can fail.
2.Aging: An aging ECU is more likely to fail as the sensors don’t work like a new one. It’s quite common sense that an aging electronic component starts failing, requiring a replacement.
3.Alterations: Most car owners are always motivated to get some accessories and modifications done in their brand new cars. A local repair guy is more likely to attempt poor installation of accessories and that results in potential damage to the ECU. Any alterations beyond the manufacturer’s advice can lead to a failing ECU, especially if the alternation is related to any electronic system.

What Factors Impact ECU Repairing Cost?

  • ECU Type & Labor Complexity
    A complex ECU will demand skilled labor for repairs, which will attract a high repairing cost. Moreover, the degree of damage, for instance, if only the wires are affected, or if the entire ECU system needs a modification, will affect the repair price.
  • Geographic Location
    Your location where you’re getting the repair done will affect the price. Getting your damaged ECU repaired by a local repair guy would be cheaper than getting it repaired from the official service center or the showroom.

Also read: Top 10 Global Automotive Electronic Control Unit(ECU) Suppliers 


So far you learned about ECU. Since a damaged ECU can be very scary, it becomes the job of IBE Electronics to take care of high-quality automotive-related PCB manufacturing. IBE Electronics is a team of skilled and professional engineers, who know very well how to make high-quality PCB boards for any vehicle.

  • ECU Helps In Engine Performance Optimization
  • It Facilitates Improved Security Systems
  • Engine Control Unit
  • Airbag Control Unit
  • Infotainment Control Unit
  • ECU Type & Labor Complexity
  • Geographic Location

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