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Using a OBD2 Scanner


Reporting and self-diagnostics capabilities are available in vehicles using a standard onboard computer system called OnBoard Diagnostics-II (OBD2). All manufacturers use the same OBD2 systems which have universal connectors, communication protocols and code designations--unlike the original OBD-I systems which were OEM specific.

The original Onboard computer system that had the ability to scan the vehicle was the Volkswagen fuel injected type 3 model. In 1988, the Society of Automotive engineers recommended a set of diagnostic test signals and standardized diagnostic connectors. in 1991 the California air resources board required all new vehicles sold in California to have basic OBD1 capabilities.

Finally in the United States, all makes and models of vehicles manufactured since 1996 were required to use OBD2 which means that using a single OBD2 scanner you could access the data from the systems of any vehicle made after that year. The OBD2 is a major Improvement in standardization and capability over the original OBD system. This system implemented standards in the electrical signal signaling protocols available, the messaging format, and types of diagnostic connectors and pinouts. The connector provides power to the scan tool so that an external source of power isn't necessary.

However, to protect the data if a vehicle should experience the loss of electrical power due to malfunction some technicians may still connect an auxiliary power source to protect data. The standardization of the OBD2 was created to help simplify the diagnostics of the various technologically advanced motor vehicles. This led to the main connector of most manufacturers being OBD2 data link connectors which all systems are reprogrammed and diagnosed.

OBD-II Diagnostic Connector Port

The SAE J1962 specification works in conjunction with type A and type B which are both the standardized hardware interfaces. They are both D-shaped 16-pin female connectors and both have a groove between the two rows of eight pins. The groove of a Type B female connector differs from type A in design only by an interruption a vertical break in the center of the groove which allows a type B male plug to insert into a type a female socket but not the other way around. This is done to differentiate the voltages in specific vehicles.

Type B connectors are used in vehicles with a 24V supply as opposed to type A connectors which are used in 12V vehicles. Also, note that type B connectors are required to be marked on the face of the D-shaped area in blue.

Different Types of OBD2 Scanners

There are primarily two different types of OBD2 scanners available to the general public, code readers and scan tools. There are also more sophisticated OEM dealership tools as well as vehicle telematics devices. However, the primary scanners will be the focus of this article.

Code Readers - Code readers tend to be the more affordable option when looking for OBD-II scanners. These devices can clear and read codes from any OBD2 supported vehicle. A major negative aspect of using a code reader as opposed to a scanning tool is that code readers sometimes lack access to other data like manufacturer specific codes in certain vehicles.

Scan Tools - The more popular and more costly option of the OBD2 scanner is the scan tool variety--which offers more features than just clearing and reading codes. Scan tools usually offer Advanced options like troubleshooting information, live and recorded data which can be customized to your liking and more importantly manufacturer specific codes.

What Exactly Do I Need an OBD-II Scanner for?

Depending on the weather you were using the original code reader or the more advanced scan tool as an OBD2 scanner, the functionalities differ. OBD2 scanners are used to read and clear codes in vehicles when running a computer diagnostic. The basic code reader version of the scanner can do this perfectly fine. However, using a scanning tool allows for more extensive options due to Software in the devices that provide other Advanced functionalities such as bi-directional controls and tests.

Of course, the scan tools Offer the basic functionality of reading and clearing codes, but they also offer the options of checking soft or pending codes that have yet to activate the check engine light. They provide data from basically any sensor that provides the onboard computer in input which can be viewed on the OBD2 scanner. Some scanners have the option of creating custom lists of parameter IDs (PIDs) and also may offer other information like giving access to readiness monitors.

How to use an OBD-II Scanner

Using an OBD2 scanner is generally easy to use since the systems are standard in all modern vehicles. The same SAE J1962 connector is used for all OBD2 ports. To use the basic scan tool version of the scanner, first, find the OBD2 diagnostic connector and insert the universal plug. modules or Keys may be included with more advanced versions of this scan tool which alter the universal connector to allow OEM specific information and controls to be accessed or interacted with.

An OBD2 scanner BlueTooth or wifi controlled via a cell phone or tablet can access information via an OBD2 scanner app making it extremely easy and clear to read and access information of your vehicle.

OBD-II Scanner Trouble Codes

Common to all manufacturers is a list of codes called standard or generic fault codes. So that any diagnostic devices can decode and read them, this list of faults also known as Data Trouble Codes (DTC) has been defined in a standard format.

The DTCs start with one letter followed by four digits. The letter indicates the DTC family as follows:

B - for Body
C - for Chassis
P - for Powertrain (Engine and Transmission)
U - for User Network


After the letter, the first digit reveals whether or not the code is a manufacturer fault or a generic one as follows:

0 - Generic Fault
1 - Manufacturer Fault


The last three digits can either contain digits or be hexadecimal or alphanumeric ( from 0-9 and A-F) as follows:

0, 1 or 2 - indicates fuel/air mixture
3 - indicates the ignition system
4 - check auxiliary emissions
5 - indicates engine idling
6 - stands for onboard computer and ancillary outputs
7, 8 or 9 - indicates transmission/gearbox
A, B or C - stands for hybrid propulsion


Standardized using ISO 15031-6 and SAE J2012 standards, these OBD2 codes were standardized and contain over 10,000 definitions as of the most recent version.

It should also be noted that these codes may not always be as efficient as needed so manufacturers sometimes take their specific OBD2 implementations and add custom data parameters to them like original trouble codes or real-time data requests.