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How Do ECUs Work and How to Read Their Parameters

Model: (Various brands) Various
Part: Control unit

Video tutorial

Let’s see how to read the data from the ECUs: first, what does CAN-BUS mean? CAN stands for Controller Area Network, which is where the data from various ECUs pass through. It is a protocol that originated in the 1980s but was used in the following decade.

The Mercedes W140 was the first car to use it; as cars began to have a lot of electronics instead of hundreds of wiring harnesses, they relied on a single high-tech CAN line (over 1,000,000 bits per second), where many sensors provide their information to multiple ECUs, as the signals do not have an address, only an identifier.

It is very reliable and immune to interference.

Through high-speed lines, it sends signals to the ECU (Electronic Control Unit) of the most important components, such as the engine, ABS, adaptive suspensions, and through low-speed lines, it connects less important systems like climate control, infotainment, airbags, etc. Then, in the 1990s, the EOBD protocol was introduced, which can communicate with the car's CAN line, providing a universal communication tool with the vehicle.

There are devices that allow users to read these errors (read-only).

A practical test follows for using an OBD11 in conjunction with a decoding app.


Updated on 19 September 2026 by ScegliAuto


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