What is OBD II? History of On-Board Diagnostics

Article Published by Geotab
Author: Victor Barreto, Senior Embedded Systems Engineer, and Paul Ciolek

You may have seen OBD or OBD II mentioned when reading about connected vehicles and the Geotab GO device. Read this post for an overview of OBD II and a timeline of developments.

What Is an On-Board Diagnostics System (OBD)?

OBD is an abbreviation of On-Board Diagnostics and refers to the automotive electronic system that provides vehicle self-diagnosis and reporting capabilities for repair technicians to access subsystem information for the purpose of performance monitoring and repair.

The OBD II port is located inside the vehicle. In a typical passenger vehicle, you can find the OBD II port on the underside of the dashboard on the driver’s side of the car. Depending on the type of vehicle, the port could have a 16-pin, 6-pin, or 9-pin configuration.

obd ii on-board diagnostics port diagram

If you want to know how to connect your Geotab GO device to your on-board diagnostics port, you can start by reading this post on device installation.

History of OBD II

The history of on-board diagnostics goes back to the 1960s. Several organizations set the groundwork for the standard, including the California Air Resources Board (CARB), the Society of Automotive Engineers (SAE), the International Organization for Standardization (ISO) and the Environmental Protection Agency (EPA).

The following is a short timeline of the major milestones in the development of OBD.

Origins of OBD

The first OBD computer system with scanning capability was introduced by Volkswagen in 1968. Ten years later Datsun introduced a simple OBD system with limited non standardized capabilities.

car exhaust pipe fumes

In 1980, GM introduced a proprietary interface and protocol capable of providing engine diagnostics through an RS-232 interface or more simply, by flashing the Check Engine Light. Other manufacturers were introducing their own versions of on board diagnostics.

It’s important to note that before standardization, manufacturers were creating their own systems. The tools from each manufacturer (and sometimes in between models of the same manufacturer) had their own connector type, electronic interface requirements, and they used their own custom codes for reporting problems.

OBD I and II Standards

1988 — Standardization of on-board diagnostics came in the late 1980s after the 1988 SAE recommendation that called for a standard connector and set of diagnostics.

1991 — The state of California required all vehicles to have some form of basic On Board Diagnostics. This is referred to as OBD I.

1994 — Three years later, California mandated that all vehicles sold in the state starting in 1996 must have OBD as recommended by SAE — now referred to as OBD II. This stems from the desire to perform across the board emissions testing. OBD II included a series of standardized diagnostic trouble codes (DTCs), some examples being

1996 — OBD-II becomes mandatory for all cars manufactured or sold in the United States.

OBD Around the World

2001 — EOBD (European version of OBD) becomes mandatory for all gasoline vehicles in the European Union (EU).

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

2008 — Starting in 2008, all vehicles in the US are required to implement OBD-II through a Controller Area Network as specified by ISO 15765-4.

What Data Is Accessible From the OBD II?

The OBD II provides access to status information and Diagnostic Trouble Codes (DTCs) for:

  • Powertrain (Engine and transmission).
  • Emission Control Systems.

Additionally, you can access the following vehicle Information via the OBD-II:

  • Vehicle Identification Number (VIN)
  • Calibration Identification Number.
  • Ignition counter
  • Emissions Control System counters

There are trouble codes covering different areas of the vehicle, such as the powertrain (e.g. engine, transmission, and emissions), body (lighting), chassis (antilock brakes), and network (CAN BUS). If you look up a list of all the standard diagnostic trouble codes, you will find pages and pages of codes for all the issues that could occur.

When a car is taken to a shop for service, a mechanic can connect to the OBD port with a scanning tool, read the trouble codes and identify the problem. This means mechanics can accurately diagnose malfunctions, inspect the vehicle quickly, and fix any malfunctions before they become a major problem.


Mode 1 (Vehicle Information):

  • Pid 12 — Engine RPM
  • Pid 13 — Vehicle Speed

Mode 3 (Trouble Codes: P = Powertrain, C = Chassis, B = Body, U = Network):

  • P0201 — Injector circuit malfunction – Cylinder 1
  • P0217 — Engine over temperature condition
  • P0219 — Engine overspeed condition
  • C0128 — Low brake fluid circuit
  • C0710 — Steering position malfunction
  • B1671 — Battery Module Voltage Out Of Range
  • U2021 — Invalid/ fault data received

OBD and GPS Fleet Tracking

The presence of the OBD II allows GPS fleet tracking (telematics) devices to silently collect information such as engine revolutions, vehicle speed, fault codes, fuel usage. The telematics device can the use this information to determine trip start and finish, over revving, speeding, excessive idling, fuel consumption, etc. All this information is uploaded to a software interface and allows fleet managers to monitor vehicle use and performance.

yellow van driving fast near bridge

With the OBD-II port, a fleet tracking solution can be connected to your vehicle quickly and easily. This is often referred to a plug and play installation. In the case of Geotab, it can be set up in under five minutes.

If your vehicle or truck doesn’t have a standard OBD II, and adapter can be used instead. Either way, the installation process is quick and doesn’t require any specials tools or the assistance of a professional installer.

Why OBD is important

The OBD is what makes telematics and fleet solutions possible. Without it, there would be no way to send all of the valuable data that your car collects. It’s because of the OBD that you can:

  • Track wear trends and see what vehicle parts are wearing out faster than others.
  • Instantly diagnose vehicle problems before they occur. Allowing you to become proactive rather than reactive.
  • Measure driving behavior, speed, idling time, and more.

In the expanding world of IoT, the number of connected devices for vehicles is increasing. It’s important to understand the difference between telematics devices. Not all devices report and track the same information. And compatibility and security can vary among devices.

Find out how to choose the right GPS vehicle tracking device in this article: Not All OBD Plug-In Fleet Management Devices Are Made Equal

With the multitude of OBD protocols, not all telematics solutions are designed to work with all vehicle types that exist today. Good telematics solutions should be able to understand and translate a comprehensive set of vehicle diagnostic codes.

Security Recommendations for OBD

Verifying the security of any third-party devices connected to the OBD II port is extremely important. To learn more about cybersecurity best practices in telematics for fleet tracking, read these 15 Security Recommendations.


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