What is an OBD Port and Where Can I Find It?

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If you bought a car after 1996, it most likely has an OBD (On-Board Diagnostics) port. In modern motoring, the OBD port has become essential as many cars are getting increasingly computerized. Today, software is vital to fixing many issues and maintaining vehicle performance.

What is an OBD Port?

OBD is an on-board digital system for monitoring speed, mileage, emissions, and other vital data about your vehicle. The OBD port allows you to easily access this system by plugging in a device that reads and interfaces with the vehicle’s computer. It is attached to the Check Engine light, which lights up whenever a problem has been detected.

The OBD port was introduced primarily following the widespread adoption of electronic fuel injection by car manufacturers in the late 1980s. Unlike the mechanical fuel injections systems, or carburetors, that were used previously, computer control is required in electronic fuel injection (EFI). The only similarity is that all these systems regulate fuel flow into the engine, but EFI does not use mechanical bits; instead, it uses electronic signals.

Where is the OBD Port Located?

The OBD port is typically found in one of two areas in a vehicle, depending on the model. In many cars, it is to the right or left of the steering wheel, underneath the dashboard. In other vehicles, the OBD port can be found in the center console, or even under the dashboard on the passenger side of the vehicle. If you’re having trouble locating the port, it could be behind a latch, or covered with a protective shield, either of which should be simple to open.Ideally, automakers design the OBD port to be easily accessible.

OBD for Diagnostics

As you would expect, OBD’s primary purpose is diagnostics. When the vehicle’s sensors detect a problem, a “trouble code” message is triggered instantly. In most cases, you’ll see the “check engine” light or some other warning on the dashboard. OBD scanners are designed to verify these trouble codes to determine the exact area of concern and wipe them off the computer memory after the issue is addressed.

Trouble codes come in the form of incomprehensible numbers that can only be translated by the use of a reference. Usually, these codes start with a letter, followed by four or five unique digits, which point towards a particular subsystem showing the exact problem it is facing. Translating these codes gives mechanics a head start in diagnosing and fixing problems.

OBD for Performance

Diagnostics is the most prominent function of OBD, but the technology also does a lot to enhance vehicle performance. 

A good number of aftermarket brands provide performance tuners alongside OBD II data loggers. These devices access vehicle systems via the dashboard port. Data loggers can track ordinary systems such as fuel economy, but at the same time, they can maintain records of power output and lap times. This is the same technology used by professional racers to track performance. The data is then used to perform a few tweaks to their speed machines.

There are companies offering performance upgrades tailored for specific vehicles that tamper with software or remap the system to unlock optimum horsepower. With modern cars heavily relying on computer controls, it’s easy to make software changes. However, many of these upgrades can impact other areas adversely. For example, if fuel economy or reliability are altered, the effect is likely to void factory warranties.

OBD Dongles

Not many people command the skill set of fixing their vehicles or upgrading their performances. That explains why companies have resorted to exploiting OBD II for more common applications known as dongles. Dongles are devices designed to plug directly into the OBD port to connect to a network wirelessly.

Sometimes dongles are issued by insurance companies to customers as a means of obtaining discounts. The structure entails utilizing data obtained from the vehicle’s OBD II connection to facilitate analysis of driving habits and reward low-risk driving behaviors with discounts. Some programs analyze speed, mileage, braking habits, and when the vehicle is driven. Paired with smartphone apps, other devices provide instant vehicle diagnosis, stolen vehicle tracking, roadside support, speed-alert features, and geofencing, among other features.

The History Behind OBD-I and OBD-II

Before the launch of the OBD-I, manufacturers created their own sets of standards. Mechanics had to part with huge sums of money to buy scan tools for each vehicle brand.

OBD-I was first launched in 1987, marking the beginning of standardization of on-board diagnostics. It was fitted with emissions sensors and designed to minimize them through special emissions-controlling valves. Unfortunately, it had too many issues.

Following the failure of OBD-I, automakers started fitting vehicles with an OBD-II port in 1996. All systems were unified, with only minimum variations known as protocols, specific to automakers. In total, there are five basic protocols;

  • ISO 1430-4 (KWP2000) – Keyword Protocol
  • ISO 9141-2 – Mainly used for Chrysler brand
  • SAE J1850 VPW – Variable Pulse Width
  • SAE J1850 PWM – Pulse Width Modulation
  • ISO 15765 CAN – Controller Area Network (applicable for all cars and trucks manufactured after 2008)

OBD-II originated in California, where the California Air Resources Board (CARB) made it mandatory for all cars and light trucks. The new standard was implemented to help with emissions control. The Society of Automotive Engineers (SAE) recommended the OBD-II standard and standardized the OBD connector and DTCs across all vehicle manufacturers. The OBD-II standard was rolled out in steps from there.

  • 1996 – OBD-II was made mandatory for cars and light trucks in the USA
  • 2001 – Made a requirement in the European Union (EU) for gasoline cars
  • 2003 – Made a requirement in EU for diesel cars
  • 2005 – Made a requirement for medium-duty vehicles in the USA
  • 2008 – Made mandatory for all US cars to use ISO 15765-4 (CAN)
  • 2010 – OBD-II made a requirement for heavy-duty vehicles in the USA

OBD-II Parameter IDs and Why You Should Care About OBD-II Data

Mechanics care more about OBD-II Diagnostic Trouble Codes (DTCs), while regulatory bodies are interested in OBD-II to control emissions. OBD-II also supports a wide array of standard parameter IDs (PIDs) accessible across most vehicles. It means that it is possible to obtain comprehensible OBD-II data from your car on RPM, speed, throttle position, and so much more.


Modern vehicles come with sophisticated systems for the ordinary driver, but on-board diagnostics such as those that Azuga reports can also come in handy. It diagnoses nearly all issues affecting the performance of your car. Whether a hose has fallen out of place, or you’re running low on engine oil, the OBD diagnoses the issue and sends in alerts in real time, giving you a heads-up on maintenance issues before they become major problems.