Home » What is OBD2? Easy to Understand Explanation!

What is OBD2? Easy to Understand Explanation!

Many drivers are very familiar with the annoying check engine light. This light usually comes on when you least expect it. Even though the light is annoying, it’s a sign that the vehicle’s system is not okay. If the light is stable, it shows that it’s a minor issue, and you can drive on. But if the light is blinking, it indicates a severe problem that has to be dealt with immediately.

Mechanics, technicians, and even drivers use the OBD1 or OBD2 to diagnose vehicle problems. But what is the OBD2 scanner?

What is OBD?

Before we elaborate on OBD2, it’s essential to define what OBD is. OBD or On-Board Diagnostics is an automotive electronic system that delivers vehicle self-diagnosis and repair technicians’ reporting capabilities. The OBD provides technicians access to subsystem data for the aim of performance monitoring and analyzing repair needs.

Additionally, On-Board Diagnostics is the standard protocol utilized on most light-duty vehicles to recover vehicle diagnostic information. Engine control units inside the car create the data. OBD is made up of the software that runs diagnostics in the background.

What is OBD2?

On-Board Diagnostics is a diagnostic system that is featured in all vehicles made after 1996. This system is used to check the engine and other vehicle systems and communicate all the possible faults that may occur. In short, it’s your vehicle’s built-in self-diagnostic system.

The OBD2 became more popular after introducing new smog regulations and increased consumer demand for technology advancements. What’s more, the OBDII system was designed by the California Air Resource Management Board (CARB), and it has been through some crucial changes since its introduction in 1996.

OBD2 history

On-Board Diagnostic 2 system dates back to the 1960s. The various organization set the cornerstone for the standard, including the Environmental Protection Agency (EPA), California Air Resources Board (CARB), the Society of Automotive Engineers (SAE), and the International Organization for Standardization (ISO). 

It’s crucial to note that before standardization, manufacturers were designing their own systems. Besides, the tools from each manufacturer had their connector type, electronic interface needs. Also, they as well as utilized their custom codes for reporting issues.  

Here is the OBD history:

1968 — Volkswagen introduced the first OBD computer system with scanning capability.

1978 — Datsun inaugurated a straightforward OBD system with limited non-standardized potentials.

1979 – One of the standardization organizations, The Society of Automotive Engineers (SAE) suggests a standardized diagnostic connector and group of diagnostic test signals.

1980 — General Motors establishes a proprietary interface and protocol capable of delivering engine diagnostics via an RS-232 interface or flashing the Check Engine Light.

1988 — Standardization of on-board diagnostics was introduced in the late 1980s after the 1988 SAE recommendation that required a standard connector and set of diagnostics.

1991 — The state of California needed all vehicles to have some basic on-board diagnostics. This is known as OBD I.

1994 — California made it mandatory that all vehicles sold in the state beginning from 1996 and beyond should feature OBD as suggested by SAE. This resulted from the need for cars to meet emissions testing.

1996 — OBD-II becomes compulsory for all vehicles manufactured within the United States of America.

2001 — EOBD (European version of OBD) is made compulsory for all gasoline vehicles in the European Union (EU).

2003 — EOBD becomes compulsory for all diesel vehicles in the EU.

2008 — from 2008 onwards, all vehicles in the US were needed to implement OBDII via a Controller Area Network as required by ISO 15765-4.

What’s the difference between OBD1 and OBD2?

Before OBD1 was introduced, every manufacturer had their personal set of standards for OBD, implying that mechanics had to spend a lot to get different scan tools from other manufacturers. The first OBD1 was introduced in 1987 and commenced the standardization of on-board diagnostics.

Besides, the OBD1 featured sensors that detected emissions and could reduce them via emissions-controlling valves. Nonetheless, it had many challenges and setbacks. In 1996, vehicle manufacturers began to fit vehicles and trucks with an OBD2 port. Most of the systems are almost the same, but with a few variations. These are referred to as protocols and are specific to vehicle manufacturers.

In short, OBD2 is the second generation of OBD or OBD1 diagnostic scanner. Moreover, the OBDI was externally connected to the console of a car, while the OBDII is now integrated inside the vehicle. OBD1 was used up to 1996 backward, while the OBDII was officially used from 1996 and later.  

How does OBD2 work?

Note that OBD2 comes with five basic signal protocols, and they include:

  • SAE J1850 PWM: Pulse Width Modulation, found in most Ford vehicles
  • SAE J1850 VPW: Variable Pulse Width can be found in General Motors vehicles
  • ISO9141230-4 (KWP2000): Keywood Protocol, utilized in various European and Asian imports and Jeep, Mazda, Honda, Land Rover, Nissan, Subaru, and much more.
  • ISO9141-2: Used in all Chrysler vehicle makes and models and various European of Asian vehicles
  • ISO15765 CAN: Controller Area Network, utilized on all vehicles manufactured from 2008 and later

Importance of OBD to motorists

The OBD is very important as it performs a variety of crucial functions. These include:

They are maintaining emission control systems in-use. This is crucial because most old and deteriorating vehicles pollute the environment a lot. Thus, knowing if a car is roadworthy or not is vital by carrying out an emissions test.

  • The OBD also helps technicians to diagnose and repair complex vehicle problems excellently.
  • It assists in keeping emissions low by detecting emission controls in need of repair.
  • Instantly diagnose vehicle problems before they take place, supporting proactive instead of reactive control.
  • Monitor wear trends and see which vehicle parts are wearing out faster than others.
  • It encourages the designing of long-lasting and durable emission control systems.
  • Provides for adequate and affordable emission inspections

How has OBD2 helped commercial vehicles?

  • Accurate data – unlike depending on the technicians, the OBD system gathers information through sensors. Therefore, this increases the accuracy of the data retrieved, reducing the probability of a vital system error to be missed.
  • Fast diagnosis – since the OBD2 features standardized connectors, DTCs, and detailed DTC systems via SAE J1939, commercial vehicle issues can be detected in a short period. All You have to do is connect a diagnostic scanner to the OBD port and retrieve codes.
  • Reduced costs – OBD2 scanners are faster, more accurate, deliver expanded monitoring capabilities, and offer improved vehicle compliance. With these functions, they have assisted commercial vehicle companies in lowering costs.
  • Different metrics – OBD systems can be used to gather different metrics apart from those linked to vehicle maintenance. For instance, they can be used to monitor driver behavior to make sure that drivers are following legal requirements and company rules.
  • Improved compliance – OBD systems also help vehicles to meet the standards set by the EPA and the Clean Air Act.

What data can I access from the OBD?

The OBDII provides a lot of information that can help motorists to keep their cars in tip-top condition. Besides, the OBD2 offers access to the Diagnostic Trouble Codes and status information for:

  • Emission Control Systems
  • Powertrain (Engine & Transmission)
  • Ignition counter
  • Vehicle Identification Number (VIN)
  • Calibration Identification Number
  • Emissions Control System counters


Understanding the difference between OBD1 and OBD2 is very crucial. OBD1 is usually applied to vehicle makes and models built before 1996, while OBD2 is used on car makes and models made after 1996.


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