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OBD1 vs OBD2: How are these Tools Different?

OBD is short for “onboard diagnostics” and it is the term for the automotive system used to diagnose or troubleshoot issues with your vehicle by returning fault codes associated with that issue.

These systems have varied greatly throughout history with the amount of technology and information both used and given. Volkswagen was the first to use onboard diagnostics in a production vehicle in the late 1960s, but these were not widely used until the 1980s.

The oldest OBD systems used a simple light that would illuminate if a problem was detected while the most advanced modern OBD systems can give thousands of specific codes indicating specific issues within each system your vehicle uses.

OBD1 and OBD2 – more officially OBDI and OBDII – are the two main types of onboard diagnostics systems used in vehicles. These systems are not the only ones used nor were they the first, but they are the most commonly found systems in vehicles today.

General Motors implemented a pre-OBD1 system in their vehicles called ALDL starting in 1980, and OBD 1.5 bridged the gap between OBD1 and OBD2 for General Motors vehicles. European market vehicles utilize the EOBD system which is basically the same as the current OBD2 system, and commercial vehicles utilize the HDOBD system – Heavy Duty Onboard Diagnostics.

What is the Difference Between OBD1 and OBD2?

The main differences between OBD1 and OBD2 are the timeframe of use, the amount of technology used, the amount of information returned, the accuracy of the information returned, and the tools used to scan and extract information from the given OBD system. 

OBD1: What is it?

obd 1 scanner

OBD1 was the first attempt at a regulated vehicle diagnostics system. California mandated that an onboard diagnostic system was placed in vehicles that would be sold in the State starting in 1991 in an attempt to regulate emissions more efficiently. As a result, manufacturers started implementing OBD1 as a “universal” system.

Despite the regulations that governed having a diagnostic system in the first place, nothing was governing the overall standardization of the diagnostic system itself. Manufacturers each used their own diagnostics systems that usually required a specific scanning tool to read. These modules required a port and hardwire that hooked up to the vehicle itself and read general fault codes that the vehicle’s computer returned. Similarly to the systems themselves and the various modules used, the connection port was also not universally placed at a specific area of the vehicle.

Though both mechanics and consumers could buy modules that could be hooked up an OBD1 port and read vehicle fault codes, the difference in the fault codes, types of modules used, and port location between each manufacturer made it difficult to diagnose issues effectively.

Additionally, because the faults returned using OBD1 were fairly generalized, very specific issues were more difficult to diagnose. OBD1 is usually limited to general engine faults, emissions issues, and fuel system issues.

OBD2: What is it?

obd2 scanner

OBD2 is the first regulated onboard diagnostics system to truly be universal. Vehicles manufactured for 1996 onward are mandated to have the OBD2 system in place.

Unlike OBD1, OBD2 scan tools can generally be used for every vehicle manufactured across brands and often do not require a physical connection between the scan tool and OBD2 port.

Most still require that a wireless Bluetooth connector is plugged in to the OBD2 port to send fault codes to the scan tool. Port locations are also generally in the same location. Most are located to the left and under the steering wheel and dashboard, above the driver’s footwell.

While the most advanced and expensive scan tools can read just about every vehicle’s computer and receive fault codes, some high-end supercars and luxury vehicles are not compatible with each scan tool available on the market. OBD2 scanners can also read OBD1 data given that the proper adapter is used, but OBD1 scanners are not able to read data from OBD2-equipped vehicles.

Another difference between OBD1 and OBD2 is the amount of information provided through the scan tool. Even though fault codes are still not completely universal, most scan tools allow the option to select the make and model of the vehicle you are scanning so that correct information can be displayed.

More advanced scan tools do not always require this initial input to work. Depending on the type of OBD2 scan tool, users can diagnose engine misfires, fuel pressure issues, engine performance issues, battery issues, and other problems with various sensors.

Advanced scan tools even allow the possibility for engine tuning, ECU tuning, and other control features over various vehicle systems.

What Types of OBD Tools are Available?

OBD scan tools are much more readily available than they used to be. With OBD1, a single scanning module could only be used on a specific make and model or only on a small number of models. With the advancement of technology, not only has OBD2 allowed for universal scan tools, but it has also allowed scan tools to be both more readily available to the public and relatively inexpensive.

There are many different types of OBD scanning tools available depending on your needs. 

Basic

Basic OBD scan tools are the simplest, least expensive, and most readily available OBD tools available. They can usually be found at any automotive retail location as well as many large general retail locations.

Basic OBD scan tools can be beneficial for those who do not typically work on their vehicle or those who want to start getting more hands-on. The most basic low-level OBD2 scan tool will be able to give users much more information than OBD1 scan tools, but they are the most similar to OBD1 scan tools of any other modern OBD2 tool on the market. 

Basic OBD scan tools are good for those who are looking to get quick, easy, occasional information from their vehicle if a problem arises. They can be found easily, are accessible to everyone, and are easy to use and read. One of the biggest cons to basic scan tools is that they may not be able to connect to some interfaces or be used on every vehicle. Even though OBD2 is universal, buyers can run into similar issues one might encounter in buying the cheapest possible computer or cell phone.

DIY

DIY OBD scan tools are often similar to basic scan tools in the amount of information provided and overall use, but they can also have a wider range of capabilities, provided information, and price point. They are geared more toward the enthusiast or hobbyist mechanic that would have more use for an OBD scanner than the average information-seeker. 

One benefit and drawback to the DIY scan tool is the variety from which to choose. Even though this gives the consumer many choices, it can also be confusing to those who are just looking to upgrade from a basic scan tool.

Additionally, some offer little to no real upgrade in information or capability from a basic scan tool, yet many come at a higher price. Despite the possibility of overlap, DIY scan tools can be a good upgrade to your basic scan tool, and some quick research can be very beneficial in pointing to a great middle-of-the-road tool that fits your budget.

Professional Grade

Professional grade diagnostic scan tools are usually the largest, most capable, most informative, and most expensive scan tools available. The most advanced of these can reach the $10,000 mark, but many can be found in the low thousand dollar region. These are used almost exclusively by professional mechanics and can be used on the widest range of vehicles. Some even offer the capability of ECU other on-the-fly vehicle system tuning.

These high-level scan tools offer the most accurate vehicle diagnostic data, often being able to give exact problem locations and return very specific fault codes. Many professional-grade OBD scanners come with additional computer software that enables their additional capability and provide the most information possible. 

OBD Port Connection Type

Hardwire Linked

obd2 port

In addition to the three main kinds of OBD scanners, there are also two main ways they can be linked to an OBD port. The oldest and most reliable way an OBD scanner can be linked is through a hardwire connection. This is a physical cord that connects the scan tool to the OBD port so that fault codes can be returned on the scan tool’s screen.

This is how OBD1 systems worked and even how some OBD2 scan tools operate. Scan tools that use a hardwire link are becoming less common as technology has progressed, however, all three types of scan tools can still utilize a hardwire link to the OBD port. Basic scan tools are the most common types to still use a hardwire link as they are usually simpler and less expensive.

Wireless

Wireless OBD scan tools have become much more popular on the market recently. They can use a variety of methods to transmit data to and through a scan tool including Bluetooth, WiFi, and smartphone application. All three main types of scan tools can utilize any one of these methods to transmit data to the chosen scan tool. 

Bluetooth and smartphone applications are the two most widely used methods to transmit the OBD data to the scan tool. A Bluetooth tool will utilize an OBD port plug-in that will send fault codes to a handheld scanner when a scan is complete.

An OBD tool that utilizes a smartphone application operates the same way, but it essentially turns your smartphone into the handheld scan tool. Even though these are increasing in popularity, there can be issues with third-party applications not connecting to the OBD port plug-in or compatibility issues with certain vehicles.

Many of the highest grade scan tools use a combination of Bluetooth, WiFi, and computer software to produce an in-depth computer integrated interface that works with the scan tool itself and the vehicle’s ECU to diagnose problem areas and program certain vehicle systems.

Final Thoughts

OBD, short for onboard diagnostics, is the system built into a vehicle that stores fault codes flagged by the ECU.

OBD1 was the first attempt to regulate and create a universal diagnostics system. Because an OBD system was only required to be part of a vehicle sold in California, this system was never truly universal and required make and model-specific scan tools to return general fault information.

OBD2 rectified this issue by creating a truly universal system in which an OBD scan tool can be used across all makes and models starting in 1996. Technology has allowed these scan tools to progress from hardwire connections with general information to wireless scan tools which can produce incredibly specific fault codes that help mechanics and regular consumers diagnose issues with their vehicles.

Shawn Furman
I have been a vehicle hobbyist for as long as I can remember as well as a freelance writer for the past three and a half years. My clients have included Vehicle Scene, Autolist, CarGurus, and now The Vehicle Lab. In addition to my current clients, I also maintain my own blog where I am able to share my knowledge and experience through vehicle reviews, car-buying guides, how-to guides, and list articles.
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