What is OBD Scanner: On Board Diagnostics Devices

OBD or “On Board Diagnostics” scanners or devices were originally designed to control the emissions in a car. But now OBD Scanners are also used to monitor critical engine components performance and other car parameters such as speed, torque, fuel parameters.

In BS6 and Euro6 vehicle norms OBD-2 is mandatory. Click this link to know in detail about AdBlue Liquid.

Applications of OBD Devices?

According to automotive norms, all components that have an impact on vehicle emission or connected to ECU (engine control unit) should be monitored and diagnosed. Apart from this, OBD devices can have following applications.

  • Indicates engine check error in the instrument cluster when a problem is detected in the engine system.
  • OBD scanner along with a mobile application is used to monitor the vehicle stats such as vehicle speed, torque, RPM, fuel parameters, battery status etc.
  • Allows mechanics to diagnose the complete vehicle by showing diagnostic trouble codes (DTC).
  • Log vehicle engine data to understand vehicle performance and driver behavior. 

How On Board Diagnostic Devices Works?

OBD system consists of ECU which gets input from sensors. As per input ECU control the engine functioning.

A vehicle ECU gets input from sensors connected to various components of the vehicle and controls the engine functioning.

In On Board Diagnosis system OBD scanners are connected to the vehicle ECU using obd connector. OBD scanner gets vehicle information using CAN Protocols and displays this data over smartphone or OBD display devices. In case of malfunctioning of any system or component, OBD sends error code to the vehicle instrument cluster as well. Detailed error code can also be determined using Diagnostic Link Connector (DLC).

Types of OBD Devices

Vehicle manufacturers use following two types of On-board diagnostics devices to get data from connected engine ECU.


OBD1 is the first generation on-board diagnostic device. For OBD1 devices, every vehicle manufacturer has their own proprietary connector and set of codes. For different vehicles mechanics has to buy different devices. OBD1 scan tools were very costly and were out of reach of common man.


OBD2 devices are a norm after SAE and ISO issued ECU and diagnostic scan tool communication protocols in 1990. After that it becomes mandatory for manufacturers to use standard diagnostic connectors (SAE J1962) and communicate via standard communication protocol. 

OBD2 Connector Pin Out

How to Read OBD2 Data?

OBD2 supports various standard parameter IDs (PIDs) along with DTC codes. These PIDs are used to retrieve various data such as speed, RPM, throttle position, fuel consumption etc. from the vehicle.

Steps to read Vehicle Data using OBD2
On Board Diagnosis system consists of ECU which gets input from sensors. As per input, ECU control the engine functioning.  In case of malfunctioning of any system or component. OBD sends error code to vehicle instrument cluster. Detailed error code can also be determined using Diagnostic Link Connector (DLC).
Vehicle and OBD Device Interaction

Data from the vehicle can be received in following steps using OBD 2 Connector.

Step-1 : Connect OBD2 device to the vehicle. You can buy Bluetooth or Wi-Fi based OBD devices from Amazon

Step-2 : Download OBD2 application for android/IOS/windows smartphone.

Step-3 : Connect application with OBD2 device

Enjoy the Live Data from your vehicle !!

We will keep updating more details on “On Board Diagnosis” used in vehicles. Please add your comments, questions or suggestions on OBD devices in the comment box.

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