OBD2 vs. CAN Bus

CAN Bus vs. OBD2: Compare Protocols and Commination Type

OBD2 vs. CAN BusWhen you buy a new car and want to repair it on your own, you must learn about the CAN bus and OBD2 scanner. As a beginner, it must confuse you. So today, we are talking about the OBD2 scanner and the CAN bus. When you learn about both systems, you can easily distinguish between this CAN bus and the OBD2 system.

What is an OBD2 scan?

The ON-Board diagnostic tools come with every single car. After 1996, attaching the OBD scanner to all cars became mandatory for safety purposes. This scanner mainly gives self-diagnostic and reporting ability. With this updated scanner, you can get many sub-system checks, such as checking engine temperature, engine speed, and so on; you can also get all the details of your car, clear the issue of the car, and control the MIL light of the car.

This scanner is now available in all cars because if your car faces any issue when you drive it, then this scanner will find it. After that, it passes the signal as an indicator on your car’s dashboard. So, from that, you can find there is an issue in your car. If you are an expert, then you can easily find the issue by yourself. But you must have some general knowledge about the OBD scanner code so that you can realize whether fixing the car is immediate or not. If you fail to learn to fix the issue, then you can get help from a professional. That will cost you some money, but it will also save you money and ensure your safety while driving.OBD2 scan Review

When you go to the car mechanic, you must see that they connect the scanner with the OBD2 pin connector. This connector is located near the steering wheel in most cars. And when the code reader gets the trouble code, it provides all the information about the vehicle, like the performance of the engine, air temperature, speed, throttle crankshaft, etc., so this scanner just makes it easy for everyone to fix any issue with their car.

Why do you need an OBD2 scanner in your car?

The OBD2 protocol helps to find the trouble in the car in the early stages; that’s why it is an integral part of the vehicle. They help to find the car’s state. This scanner has a self-diagnostic function that is used to monitor all functions of the car. This system mainly helps you to maintain your car in a very easy way. You can get a lot of information from the OBD scanner, like mileage, speed, emissions, engine state, etc.

This system not only detects the problem in the car but also teaches you about the engine’s performance. The keys covered include engine misfire, speed control, transmission, fuel system, and so on; it can also process fault issues such as engine revolutions, fuel usage, vehicle speed, and so on.

What is the CAN bus in a car?

If you think about it now, what is a CAN bus in a car? CAN is mainly a Controller Area Network, which is a bus of the network that has independent controllers communicating securely. Bosch and Intel 1990, first came up with this bus system, and after that, it’s mandatory for every car now. The ISO or International Standards Organization defined that this CAN be using their OSI model. If you look at this on the physical side, you will notice there are two dedicated wires for communication, one for low and another for high. These two wires mainly help to connect a connection between modules and devices of the vehicle. And this message-based protocol helps to communicate with the microcontroller of a car’s automobile and other reliable devices, maintaining the priority proven list.CAN bus in a car

What is the need for this CAN bus?

As I said before, the CAN bus connects and enhances communications between the electrical control units, but it doesn’t require any computers. But it also has many applications like aircraft, aerospace, cars, trucks, us, etc., automation systems. On the one hand, the CAN bus gets power from its wire; on the other hand, it also has another power supply for CAN bus modules that are arranged totally separately from the previous one. You also get a four-wire system CAN bus on the market. And it also acts just like the previous one.

Now, CAN buses use data frames for communication purposes. There are a few frames used in there like a frame can be a data frame, an error frame, etc. with stop and start bits, CAN ID or address, data, check bits, etc., so when you start your car, the CAN bus also starts its work to find the status of the message. When the engine speed sends a continuous message to the CAN bus, the ECU gets that message, and the tachometer of the arm is used to update itself when it gets an updated value.

CAN BUS vs. OBD2: Key Differences

Are OBD2 and CAN buses the same? No, both are two types of elements that come with every car. The main difference between these two are:

Communication system:

OBD2 has a higher layer of protocol; that’s why it has a language used for diagnostic functions. On the other hand, A CAN bus protocol acts as a medium of communication between different parts of a car, automobile, or any other device.

Compare Speed:

While the CAN bus is a high-speed communications protocol, that means it needs less time to communicate. But, OBD2 is a slow way of reading data to show it on a digital screen. 


The CAN devices broadcast to the network for any device connected to read; you don’t need to ask for it. But OBD can’t have this function.

Data passing access:

CAN have no restriction to sending or receiving data from many data sources. But OBD2 devices are limited to sending and requesting one data source at a go. 

What is the similarities between OBD2 and CAN bus:

Both OBD2 and CAN bus protocols are mainly used for communication purposes. They both use identical connectors, J196. That’s why many people get confused and think that both are the same thing for a car.


In the end lets, you must know that a converter is used in both protocols to transfer the data from OBD-II to the CAN bus, and it also works vice versa. The converter mainly converts the CAN signal so that it can easily fit into the OBD2 scanner. After that, it can give the most important message. This just extracts and converts the information from the CAN bus network to readable for car owners or mechanics. That’s why many people think both are the same and used for communication purposes. But this protocol is different, CAN bus is used to make communication between car automobile to other devices; on the other hand, the OBD2 function get information from ECU, and it allows to control of some unit like brake, steering wheel, etc. to engine, airship, etc. but it doesn’t need any host computer to perform this communication.

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