OBD2 vs CAN bus. What are the differences?

OBD 2 and CAN buses are easily confused protocols in a vehicle. However, these two protocols have different roles and work differently. If you want to dive into details and understand how these two works relate, work together, and differ, you are in the right place. The article will outline the essential information you need to know about these two protocols. 

What is OBD2?

The On-Board Diagnostic protocols or the OBD2 is the car’s built-in self-diagnostic system that monitors and receives information from the ECU ( Electronic control units).

If you have ever noticed the malfunction indicator on your dashboard, that is your vehicle’s way of signaling you that there is a problem somewhere. If you take your car to a mechanic, you will see the mechanic use an OBD2 scanner to diagnose the problem. 

The mechanic will connect the reader to the OBD2 pin connector located near the steering wheel for most cars. He will read the OBD2 error codes, which will help him review the problem and troubleshoot it. Therefore, an OBD2 or onboard diagnostics 2 is a protocol that aids in reading a car’s state by using a diagnostic scanner. 

This regulated system is available in small trucks and vehicles and used for self-diagnostics. It has a 16 pin port near the driver’s seat. The obd2 connector allows you to access data from your vehicle with ease. 

What information can OBD2 provide?

It provides information about a vehicle’s coolant, air temperature, road speed, position, throttle crankshaft, and camshaft, plus the engine rpm and, most important aspect, the problems that your car has. 

What is OBD2 used for?

The OBD2 protocol is an integral part of a car as it helps in the early troubleshooting of problems. They help in revealing the car’s state. This proximal is used for self-diagnostics of the vehicle since it monitors and regulates its various functions. 

Moreover, the system helps in maintaining a car’s multiple systems. An OBD2 also self-corrects abnormalities in a vehicle’s fuel mixture and ignition. The obd2 is used in monitoring mileage, speed, emissions, and any other information about a vehicle.

The system monitors and detects issues across all areas that impact the performance of an engine. The key aspects covered include

  • Engine misfires
  • Speed control
  • Transmission systems
  • Fuel systems

The OBD2 enables the telematics devices to process information like fault codes, engine revolutions, fuel usage, and vehicle speed. 

What is a CAN bus?

A controller area network or CAN is a protocol created to permit microcontrollers or control units like the brake and engine to communicate with one another without a host computer. CAN eliminates the point-to-point communication approach and reduces the wiring quantity and complexity. 

It allows for faster communication between modules and devices in vehicles. This message-based protocol allows microcontrollers in automobiles and other devices to reliably communicate with each other in a priority-proven way. 

What is it used for?

The CAN bus is used for enhancing communications between the electrical control units without using any host computer. Therefore, it is employed in multiple applications like aircraft, aerospace, cars, trucks, buses, and factory automation. 

Applications for CAN bus

  • All types of vehicles
  • Elevators
  • Manufacturing plants
  • Dryers, washing machines, and other household appliances
  • Ships
  • Heavy-duty telematics

Differences between OBD2 and CAN bus

  • A CAN bus is a protocol that acts as a mode of communication between different parts of an automobile or any other device, OBD 2, on the other hand, is a higher layer of protocol, in other words, a language used for diagnostic functions. 
  • While CAN bus is a high-speed communications protocol, OBD2 is a slow way of reading data on a digital screen. 
  • Unlike OBD2, the CAN devices broadcast to the network for any device connected to read without necessarily asking for it. 
  • OBD2 devices are limited to sending and requesting one data source at a go. On the other hand, CAN is not restricted to this because it includes several data source values in one message. 

Similarities between them

  • Both OBD2 and CAN bus are protocols that are used for communication purposes. 
  • They both use identical connectors, J196. 

Can they be confused? 

The two can easily be confused though different. A converter can transfer the information from OBD 2 to the CAN bus and vice versa.

This converter is a CAN signal converter that can fit into the OBD 2 socket and provide helpful information by extracting and converting engine information from the vehicle’s CAN bus network. 


OBD 2 and CAN bus are communication protocols used in automobiles and other devices. While they seem to perform similar functions, they are different. The OBD2 monitors and receives information from the ECU while allowing control units like the brake and engine to communicate without a host computer.

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