For a human, if any problem will occur we can feel it and we will go to the hospital where the doctors will do the diagnostic and give the medicine for the particular problem and we will cure the problem or disease. Like this for a machine, mostly the electronics control units are having there own ECU fault codes which are used to find a particular area fault by doing the proper diagnostic.
But the machine can’t feel the problem as like vehicle that is what the difference between the Man & Machine. So to make the machine-like human nowadays, the vehicle manufacturer’s are implementing the different diagnostic protocol like UDS protocol in the ECU to do the diagnostic and make a solution for a problem without opening or touching the hardware parts which might make them more difficult for a vehicle at risk, high cost, time is taken, etc. So the OEMs are implementing the Diagnostic Trouble Code (DTC)for any fault that occurs in a vehicle. In each vehicle the OEM implementing the DTC in each ECU that named ECU fault codes.
When the vehicle designed first, there are no electronic components were used. So if any problem was happening, the mechanic was supposed to repair this. The mechanic mostly not having a lot of knowledge, they will work in some garage for some years, after getting some experience they will be a mechanic. At that point, it had been fine that they will roll in the hay since there wasn’t much knowledge required. But nowadays if you’ll look onto any vehicle there are numerous features like a robot. So they will be having a lot of computer system nothing but the Electronic Control Unit (ECU) is there. These are having a lot of functionality that can run your vehicle automatically. Even it also can think about what to do next. Though it is having a lot of features, they also need a smart diagnostic program that can detect the ECU fault codes for better maintenance service.
Now if you will think about the vehicle diagnostic, then it is a bigger hologram for automotive vehicles. Because the total vehicle is having ECUs and 60% functionality of a vehicle is automatic. Even if the driver is also not required for some time in current technology. And in the next 5-10 years, I hope there is no need of driver that the vehicle is self-sufficient to control the vehicle having pure robotics technology. So when any fault will occur in the vehicle you can not predict where is the fault by a mechanic. You need to have a proper educated engineered diagnostic engineer who can have this knowledge to diagnose your vehicle. So that he can get to know the ECU fault codes in that
Basically the diagnostic is two types in automotive vehicles, such as one is On-Board Diagnostic, and the second one is off-Board diagnostic. The On-Board diagnostic is a method in which the ECU itself is having some internal self-diagnostic programs that are running periodically. They can detect if any fault will happen in any module. These faults are having a unique value which is also defined in OBD-II standard document for universal use. And also they will store all these data inside the permanent memory of the ECU micro-controller. So whenever you want these data also can read by using the OBD-II code reader or some people are calling it an OBD-II scanner.
The Off-Board diagnostic is a method to do diagnose a vehicle by connecting an external computer system, or any wireless tool also available nowadays. Even if you can also connect your android mobile by Bluetooth for diagnostic purposes. By connecting the external diagnostic computer you can also read the fault codes stored in your vehicle computer nothing but the ECUs. If you are not able to fix it then also you can do more analysis by reading your vehicle engines data like engine speed, engine RPM, any sensor data, any actuator data, or anything as whatever it should have implemented by the OEM with the maximum feature. After getting these data you need to analyze and fix the issue. So the things can not be possible by a mechanic.
So, in conclusion, I can say If any fault will occur, the OBD (On-Board Diagnostic) will detect the fault and set the particular fault. This fault or MIL (Malfunction Indicator Lamp) will indicate to the driver in the LCD screen on the Cluster. So if it is normal and the driver can fix it then he will do or else he will go to the Service center where the diagnostic engineer will connect the computer, or nowadays also the android app is available for portability and they will start reading the Faults as DTC from the vehicle and repair the vehicle which is very easy and flexible.
Enjoy the Vehicle Diagnostic………