How it works – OBD2 Scanner

OBD II Scanners are devices that are used to access car OBD (on-board diagnostic) information. They are found in most cars and light truck models released in recent years. During the late 70s and early 80′s, motor vehicle manufacturers started using electronic methods to control the functions of motor vehicles as well as diagnose engine problems.

The primary reason for this was to meet EPA (Environmental Protection Agency) emission standards. Over the years, OBD II Scanners became more sophisticated with a new version coming out in the mid-’90s providing “almost” complete engine control. That same OBD version also made it possible to monitor parts of the chassis, body and accessory devices, as well as diagnose the entire control network of the car.

Prior to the introduction of the OBD II Scanners automobiles had connectors in several positions under the dashboard and the hood. Now, they have a connector located in the passenger-side compartment which is easily accessible from the driver’s seat. The OBD-II J1962 connector has a cable plugged into it and then connected to the OBD II Scanner. A computer in the vehicle continuously monitors all aspects of the car’s operation. As soon as a problem is detected, a trouble code gets saved immediately into the vehicle’s computer memory. Some of these problems automatically trigger warning lights such as the Check Engine light, while others simply store the data as needed.

Consequently, OBD II Scanners can read the DTCs (diagnostic trouble codes) to identify specific problems. When an issue is encountered, the car owner can look up the meaning of the code in display and refer to troubleshooting manuals to find ways of fixing it. The codes’ meanings are normally supplied by the manufacturer in a hard copy, or soft copy which can for easy retrieval via any computer.

Consistent with the OBD II functionality, the Check Engine light on the dashboard is known in the service industry as an “MIL” or Malfunction Indicator Light. It displays three types of signals. When occasional flashes are displayed, this would mean momentary malfunctions. If the problem is serious then it flashes continuously, and this normally occurs when the problem has to do with emissions or the vehicle’s safety. When the MIL has a constant flash, this indicates a serious problem which requires an immediate response. Failure to respond to this state of the MIL alarm can lead to engine damage.

Serious failure signals causes the MIL to be turned ON any time the vehicle is running and will not turn OFF until the MIL is reset or the problem is fixed. Occasional and random failures causes the MIL to light instantly but these often go out before the problem is located. The freeze frame of the vehicle’s condition captured by the computer at the moment of malfunction can be very valuable during problem diagnosis. In some cases if the vehicle finishes three driving cycles without the problem happening again, the freeze frame will be erased.

All of these are handy descriptions of what OBD II scanners can do to make your car safer and easier to troubleshoot. The advances in control technology have allowed more sophisticated control systems to constantly check your vehicle so you will not have to worry when driving.

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