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OBD2: Everything About It

Looking for detailed information about OBD2?

You have come to the right place where you can find what you want! All manufacturers use OBD2 to monitor and diagnose car issues and emissions so it will be beneficial for you to know about this technology.

This article will give you not only the general definition of OBD2 but also the technology, application, and 10 modes of the OBD2 system.


OBD2 is the same system required to be used by all
OBD2 developed to meet the EPA emmission standards

Onboard diagnostic systems have been used in cars since the 1970s and 1980s to diagnose engine problems. These systems were primarily developed to meet the EPA emission standards to protect the environment from becoming polluted by car emissions.

Over the years, OBD technology has become more advanced and standardized, which is where OBD2 comes into play. OBD2 is the same system required to be used by all car manufacturers to monitor and diagnose car issues and emissions.


OBD2 technology monitors more than just emissions. It looks at all engine functions, ABS breaks systems, SRS airbag systems, fuel economy, and much more.

Because it is required to use the same interface for every car, it’s easy to find scan tools that allow you to read the data on your car. OBD2 provides a universal diagnosis and inspection process to make sure all cars are meeting emission and performance requirements.

OBD2 diagnostic connector

OBD2 connector is the same connector for every car

OBD2 connector is a 16-pin port.

In the past, car manufacturers could create their own OBD systems, so they varied from one car model to the next. This made it hard to read diagnostic information from car to car, so a universal OBD2 diagnostic connector was established.

This connector is a 16-pin port. It is the same connector for every car, so reading OBD2 systems are much easier. However, not every car model or OBD scan tool uses all 16 pins to send and receive information.

OBD2 protocols

Current OBD2 standards permit five different protocol types – ISO 14230-4 (KWP2000), SAE J1850 VPW, SAE J1850 PWM, ISO 15765-4 CAN, and ISO 9141-2. Though the 16-pin plug-in port on most modern vehicles appears visually the same, their 16-pin arrangement and function differ from protocol to protocol. Most modern scanners can read any protocol type, but it is still essential to know your vehicle’s specific protocol.

Learn more: OBD2 Protocol: What Is It And Which Protocol Does My Vehicle Support?

OBD2 codes / OBD2 PIDs

OBD2 codes, also called Parameter IDs (PIDs), are used to tell you what is going on in your vehicle. You can use them to request data from your vehicle and read them with a diagnostic scan tool.

There are tons of different codes, some are standard on all vehicles and some codes are specific to different models of cars. Some of the standard codes are P0171 System Too Lean (Bank 1) and P0440 Evaporative Emission Control System Malfunction.


There are a few different OBD2 application
OBD2 application that plugs into the diagnostic connector can translate the information for you

In order to communicate with your car’s OBD system, you’ll need an application that plugs into the diagnostic connector and can translate the information for you. There are a few different application options that you can do this with

OBD2 cable scan tools

These are the most basic type of scan tools that are handheld devices that connect to your car’s connector via cable. You plug them into the connector, and the reader scans the codes and relays the information to you on the screen.

There is a wide range of cable scan tools, ranging from simple code readers to professional diagnostic tools. As the cable scan tool becomes more advanced, the price tends to increase. You can get a cable scan tool for as little as less than $100 or as expensive as $700 or more.

OBD2 Bluetooth scanners

This is a new version of OBII applications that plug into your car’s connector and then send the information via Bluetooth to your phone or other Bluetooth devices.

You must use a corresponding OBD2 app on your device to look at all the information communicated via the Bluetooth scanner.

This application is a very convenient and easy way to read the diagnostics on your car. Unlike the cable scan tools, the Bluetooth scanner displays the information in an easy way for you to understand explanations and graphs rather than just a set of codes.

OBD2 PC-based software

You can also read the OBD2 information on your PC laptop. These applications are similar to handheld scan tools, except they give you much more information and it’s easier to read the interface.

To do this, you can purchase an OBD2 adapter with a USB plug that goes into your laptop and then downloads the necessary software to read the information.

Data loggers

Data loggers are similar to OBD diagnostic tools, except that they record your car’s information such as vehicle speed, RPM, and throttle position, and then save it onto an SD card in CSV format.

Emission testing

You can also easily perform emission testing with OBD2. In the past, this was primarily done through tailpipe tests, which were not as accurate or fast. Now you can easily test your car’s emissions with an OBD2 scan tool.

Driver’s supplementary vehicle instrumentation

This is the instrumentation installed on a vehicle and the normal instrumentation provided by the car manufacturer.

These are gauges that show customizable data information to the driver during normal operation. These are similar to other scan tools but provide specific information that a driver chooses.


There are 10 different modes used by OBDII systems that allow you to read the raw data. Not all vehicles support all modes.

Mode 1

This mode shows the current data in the system, such as engine speed, engine temperature, and vehicle speed.

Mode 2

This shows the freeze frame data of a fault, which is sensor data record instantaneously when a fault is detected. Mode 2 allows you to see what was happening at the moment the fault occurred.

Mode 3

This mode shows the stored Diagnostic Trouble Codes (DTCs). These trouble codes are standard for all car makes and models and start with a letter followed by 4 digits.

There are 4 categories of codes: P0xxx, C0xxx, B0xxx, and U0xxx. P0xxx codes relate to the powertrain (which is the engine and transmission).

C0xxx codes have to do with the chassis, B0xxx codes have to do with the body, and U0xxx codes have to do with the communications network. This mode is the most commonly used.

Mode 4

This mode allows you to clear DTCs and stored data. You can reset the fault codes and erase any stored data.

Mode 5

In this mode, you can see the results of the oxygen sensor monitoring systems (for non-CAN systems only).

Mode 6

This mode shows the scan results of other sensors that are not required to be monitored continuously.

Mode 7

This mode shows you pending DTCs that have been detected during the current or previous driving cycle but aren’t confirmed.

Mode 8

This mode allows you to see self-diagnosis reports of other systems such as fuel pumps and idle valves.

Mode 9

This mode allows you to request vehicle information such as VIN and calibration values for your specific vehicle.

Mode 10 (Also called Mode A)

This gives you the permanent DTCs, which cannot be cleared like in modes 3 and 7. You can only clear these stored DTCs after several driving cycles with no detection of the codes.


Most vehicles have OBD-II

If your car was manufactured in the 1995 or 1996 model year, then your car has OBD-II

Although it may seem confusing to figure out if your car has OBDI or OBDII, it’s actually quite simple. If your car was manufactured before 1995, it uses OBDI.

If it was manufactured starting in the 1995 or 1996 model year, then your car has OBD-II. Most vehicles have OBD-II unless it’s a very old model. So you will need an OBD-II diagnostic tool to be able to read your car’s diagnostic information.

Other posts related to OBD-II you may interest in:

BlueDriver OBD2 Bluetooth Scanner for iOS & Android Review

OBD2 Protocol: What Is It And Which Protocol Does My Vehicle Support?

Best OBD Scanner: Complete Review And Buying Guide 2020

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