Your Car, Your Computer: ECUs and the Controller Area Network

The before, a shade tree mechanic could identify the problem and repair his car with a degree of ease.

I spent numerous hours working with my dad in my youth on our cars – changing parts, adjusting timing, altering fuel mixtures, and working on brakes – you can think of it. He was an aviation mechanic during WWII and spent over 32 hours as an electrical engineer in the factory.

In the present, that experience may not be enough. This type of job requires an increased level of technical expertise and computer knowledge.

Your car is now more than a mere mechanical vehicle. Instead, it’s an electronic system with great complexity. In reality, your vehicle may even be a collection of computer nodes connected with a bus network. The nodes are described as electronic Control Units (ECU) as well as the network topology is referred to as”the Controller Area Network (CAN).

Electronic Control Units

ECU is the general term for electronic devices that manage electronic systems that are used in modern vehicles. There are various kinds of ECUs, and their functions differ. The most well-engineered cars could have up to 100 ECUs. These ECUs perform different functions, such as:

  • Engine control
  • Control of transmission
  • Control of the brakes
  • Speed help
  • Park help
  • Automatic climate control
  • Traction control
  • Control of the anti-lock brake system
  • The terminology used for the name may vary among manufacturers of automobiles. The ECU that controls the engine can be referred to as an “engine control module” (ECM), also known as an engine control module (ECU). This dual usage of ECU to mean the generic electronic control unit or a particular engine control unit could confuse. Most often, the engine control module, as well as the device that regulates the transmission, are both parts of an ECU known as”the powertrain control module (PCM). Many people consider that ECM and its PCM in the context of a “Central Processing Unit (CPU)” of the car.

    The reality is that the different ECUs used in the vehicle have distinct functions and act as separate nodes in the car’s network structure. It is just the beginning! (For more information on the tech used in the modern automobile, read this article about autonomous vehicles (“Are These autonomous vehicles ready to Survive in Our World?”) And think about how much of this type of technology is already being used in models that are rolling off those lines!)

    Manufacturers have set ambitious objectives to enhance and improve the technology in their automobiles. The utilization of ECUs and other systems has brought about evolution towards what’s known as “lidar,” also known as “laser radar,” which is a sophisticated system of sensors that enable the vehicle to “see” the environment around it, which allows for the introduction of warnings about lane departures automated braking, and other features discussed above.

    Carmakers are also innovating ways drivers interact with their cars through biometric systems and cutting-edge control systems that render key ignitions and steering wheels obsolete.

    ECUs enable these improvement procedures to be automated and can be implemented in real-time. In a closed-loop system, several sensors collect data from the network and transmit com

  • mands to actuators, providing the necessary actions to achieve the highest quality outcomes. The output of sensors is sent to the system to inform it of what the vehicle is doing, and the subsequent input of the new instructions is used to make the needed adjustments. The ECUs make use of the data that sensors provide like:
  • Engine coolant temperature sensor
  • Sensor for the temperature of the air
  • An absolute pressure sensor in the manifold
  • Sensor for mass airflow
  • Idle air controller
  • Crankshaft sensor
  • Camshaft sensor
  • Oxygen sensor
  • Knock sensor
  • The parts of an ECU comprise analog-to-digital converters, signal conditioners, converters for digital to analog communications instruments, chips, and intelligent sensors. Information that comes in as analog may be converted into digital to enable electronic processing. All of this information is transmitted via a bus topology known as controller area networks.

    Controller Area Networks

    It’s a computer network with a digital interface that communicates with various ECUs in the car. Each ECU node is responsible for data input and output data when it interacts with the electrical and mechanical elements of the vehicle. For instance, information such as ambient temperature, coolant temperature airflow, and acceleration positions are processed and subsequently acted upon employing fuel injection, ignition timing turbo boosts, and the like. Thus, the CAN networks are an ongoing feedback loop?

    It is believed that the CAN protocol stack could be considered as that of the OSI model’s two layers below. This OSI physical layer is linked to three physical layers of the CAN model. The layer for data is compatible with the logical linking control (LLC) and media access control (MAC) layers of CAN.

    The Controller Area Network bus was created in 1983 by Robert Bosch GmbH 1983. Each CAN node is comprised of a microcontroller, a CAN controller, and a transceiver for CAN. The CAN protocol is a message-based one that uses one of two identifiers: 11 bits (standard format) or an identifier of 29 bits (an extended structure that includes 18 additional bits). The components of the CAN bus comprise hardware and software (actually firmware), which can be altered and tweaked using other chips or even software command?

    CAN utilize an arbitration procedure to control traffic compared to CD/CSMA the Ethernet protocol. In the context of vehicle technology, it can be supplemented with other techniques, like Flexray, which utilizes TDMA and can operate at up to 10 megabits per second, or Local Interconnect Network (LIN) that is a single wire standard network protocol. There has been some discussion for replacing Flexray with Ethernet that would offer certain advantages. The CAN bus is one of five protocols accepted by the technology known by onboard diagnostics (OBD).

    Onboard Diagnostics (OBD)

    OBD-II replaced the initial OBD in the year 1996. The initial goal was to control emissions to meet government regulations; however, the latest version has been adapted to incorporate various functions. As a digital diagnostic, OBD-II uses an extensive database of codes, which you can find at For instance, the P0171 code is a generic powertrain code that indicates “the system isn’t sustaining enough.” Five-digit regulations are interpreted as follows:

  • [Alpha]-area (Body, Chassis, Powertrain, U – network)
  • Manufacturer’s code
  • System
  • Troublesome issue
  • You can access the OBD-II data from your car by a variety of methods. Most auto parts stores will offer a device that plugs into an electronic port beneath the dashboard. You could also buy an auto scanner and use it to read the code described by Wikihow. You can also hack into the computer in your car using the appropriate cables, your laptop, and a dedicated program. A few of the graphic interfaces offer a great insight into the functioning of the computer in your car. Be conscious that whatever hacking you undertake, you do so at the risk of your safety and not suggested by the manufacturer of your car or this site!


    We’ve stated the car you drive is an electronic computer. In reality, it is composed of multiple computers that form an intricate network. The processors in your latest car can offer advanced engine control, modern diagnostics, advanced safety or comfort options, and even a decrease in wiring. The benefits of the newest car computing provide a wealth of advantages, although some may argue that the simplicity of repair for your vehicle repair is gone.

    As I worked with my dad when I was a kid, I never thought that my knowledge would be as good as his knowledge of car repair. So it’s now me wondering if all the years of experience as a network engineer could apply to this.

    I’m also curious about how long it’ll be before cars become self-aware like the car David Hasselhoff drives in the television series “Knight Rider.”

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