How Does OBD (On-Board Diagnostics) Works?

by Jatin Chhibber | 06/04/2021
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Here’s how an OBD system works and what are the benefits of On-Board Diagnostics. 

OBS- Purpose

The aim of the OBD systems keeps changing with time. As the name suggests, On-Board Diagnostics is mainly used for vehicle diagnostics. The device is used to monitor several parameters inside a vehicle’s powertrain. It is an electric component, which communicates with all the other electric components of the vehicle. This consists of getting data from all the sensors and sending error signals to the ECU (Engine Control Unit) of the car. ECU is like the brain of the computer, which stores and corrects the data from all around the vehicle. The Engine Control Unit will easily recognize the error signal and will send the corrective signal to repair the problem. Just by the action of ECU, a ton of errors can be fixed.


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This consists of ignition timing stop knock inside the power plant, and it sends a signal to the fuel injectors on the amount of fuel to be injected into the cylinder for the whole combustion process.  For example, if a driver fully presses the accelerator pedal, which means that the driver wants to accelerate faster and more power is required. Thus, more fuel needs to be injected into the combustion chamber to make more power. The ECU makes sure that these changes are made within a fraction of seconds. For Instance, if there’s a knock inside the combustion chamber, the On-Board Diagnostics will show a sign on the instrument cluster, and the ECU will slightly delay the ignition timing and the knock will be fixed. 


If for some reason, the emission levels of a car are heightened, the On-Board Diagnostics comes in handy. It will show that something like this is happening inside the vehicle. If the issue can be fixed by ECU, it will fix the issue. If not, the driver will get to know that he needs to take the vehicle to the service centre to get the problem checked and fixed. Moreover, one can keep an eye on several parameters during the actual operation of the motor. The OBD port will be attached to the laptop, and a person can get a real-time reading on various parameters to find out if any specific component of a car is malfunctioning. One of the main purposes of OBD is emission testing because it offers real-time figures of the amount of NO, CO and other exhaust elements. 

OBD- History

OBD was first introduced back in 1969 when VW first launched On-Board Diagnostics with scanning capabilities. At that point in time, the necessity and trend of having computers on vehicles started. There was a successive enhancement in this area by other carmakers as well. But the On-Board Diagnostics, we know today was introduced back in 1988. As compared to 1969, computers had more computing power. The first OBD was known as OBS-1. The main feature of this system is that it controls the emission and also monitors the real-time parameters of the vehicle. The biggest problem with this system is that it has no standardization in terms of letters denotes what. If OBD finds out some issue, the way it would indicate it would be very much different for other automakers. Thus, the error could mean different things for different kind of vehicles. There are several ways to read the parameters of a car. Every vehicle gets an interface port, where a person can connect an electronic device to go through the required parameters of the vehicle.


Code Readers
To read the parameters of a vehicle, a hand scanner or reader is one of the most basic devices. It gets a small display that goes via all the parameters and informs you if there is a fault anywhere in the system. The display is not too detailed, and the device is quite inexpensive. 

To read all the codes via the OBD system is through connecting it to a laptop as it is one of the most widely used and effective methods. The car mechanics in the authorized dealerships across the country use laptops as it gives an overall view of all parameters of the vehicle. Moreover, it is also a much faster way to check all the dimensions at once.


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Applications on Smartphones

Nowadays, all cars are offered with Bluetooth connectivity option as standard. This can also be extended to the OBD system. A person needs to install applications on smartphones to read the code from an OBD system. Through this one can easily know what is wrong with his/her vehicle.

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