On-board diagnostic abbreviated as OBD refers to a vehicles self-reporting and diagnostic capability. OBD system provides information about the vehicle sub-systems to the owner of the vehicle or the technician. The technician can use OBD to identify the part of that is malfunctioning. The amount of information provided by OBD depends on the type of device used. The first OBDs could only pinpoint a problem in the vehicle by illuminating the malfunction indicator light. It wouldn’t provide any information about the nature and extent of the problem. However, due to advancements in technology, there are modern OBDs that can show all the information about the vehicles sub-systems. They diagnose all the problems in the vehicle. This makes the repair of the vehicle very easy.
OBD II is an improvement of OBD I. OBD I was developed was designed with the intention of encouraging auto manufacturers to manufacture vehicles with reliable emission control systems. The idea was that, if the vehicle had a good emission control system, it would last long. The owners of the vehicles were supposed to take their vehicles for annual emissions testing to California. The authorities thought that, this regulation will make drivers opt to buy vehicles with reliable emission control systems. However, this idea failed because there was no standard control system for all the vehicles. The annual testing program was also unsuccessful due to the fact that, there were technical difficulties in establishing the emissions from every vehicle. This made it necessary for the developers of OBD I to develop a better device which is OBD II.
OBD II standard format clearly specifies the type of diagnostic connecter and its pin out, the messaging format as well as the available electric signaling protocols. The device also provides a candidate list. This list contains the vehicle parameters to be monitored and the method to be used in encoding data for each parameter. This means that, each subsystem in the vehicle will be monitored and the status of each shown in the list. You will also not have to connect the scan tool separately to a power source. This is due to the fact that there is a pin in the diagnostic connecter that provides power from the vehicle battery to the scan tool. However, you can still connect the scan tool to an auxiliary power source in order to protect the data in case the vehicles electric system fails due to vehicle malfunctioning. The other feature of OBD II is the extensive list of Data Trouble Codes. The trouble codes are four digits that are preceded by letter B for vehicle body, P for the engine and transmission, U for network and C for chassis. Because of the standardization of the OBD II devices, any device can query any on board computers in the vehicle. There are two models of OBD II device; OBD IIA and OIBD IIB. Most manufacturers of the OBD II device ensure that the device has only one Data Link Connecter through which all vehicle systems are diagnosed. OBD II is a device you should not miss in your vehicle. The device will not only monitor the sub-systems in the vehicle, but also make its repair fast and efficient.