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What Does an Electronic Control Module Do?

by Andrea Stein

Cars rely on a number of electrical and mechanical parts to run properly. These parts are controlled via a central processing unit in the car called the electronic control module.


An electronic control module, also called an electronic control unit, is the embedded system used to control the functions of electrical systems contained within a motor vehicle. An embedded system is a computer system consisting of mechanical and hardware parts used to perform one or a few dedicated functions.


A car’s electronic control module functions using closed-loop control, or a type of control scheme designed to monitor the outputs of a system in order to control inputs sent to the system. The electronic control module receives data via dozens of sensors in the car’s electrical systems and performs calculations to determine such factors as the fuel-ignition timing and the time a fuel injector should remain open.


A typical modern electronic control module contains a 32-bit, or 32 basic units of computer data, processor. The code used in an average electronic control module consumes less than one megabyte, or 1,048,576 bytes of memory. The programs on an average computer contain at least 2 gigabytes of code, more than 2,000 times the amount of an electronic control module.

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