The Latest in Auto-Techo: What is an OBD II Code Scanner?

OBD stands for On Board Diagnostics. This literally means diagnostics can be made on a vehicle with the use of a code reader and/or scanner. The "II" stands for the second 'version' after 'OBD I'. The first 'OBD' covered Ford and Chrysler vehicles 1983-1995, Jeep vehicles 1991-1995, and GM vehicles 1982-1995. Imported vehicles and other makes used other diagnostic standards prior to 1996. OBD II covers all vehicles manufactured from 1996 to present. The Reader and Scanner diagnostic equipments both display vehicle computer fault codes with descriptions. Scanners have the additional function of providing real-time component voltage and current outputs. Examples of these components are: Oxygen Sensors, Fuel Injectors, Ignition Timing Sensors, Throttle Position Sensors, and Coolant Temperature Sensors.



OBD II Code Scanners with the help of automotive repair manuals are better in the sense that it displays the computer error code and at the same time identify the sensor involved. The good thing about them is they can be used in almost all makes and models of vehicles. Some might have the notion that the scanner is a tool that could fix a cars problem. The function of the OBD scanner is to scan the computer system of a vehicle and read the error code that is causing the problem. In some cases it is just a matter of erasing the error code and everything should be fine again. For intermittent occurrences of the problem it might no longer be just erasing the error code. There could already be a problem on the sensor causing the error code, if not the engine control unit or module (ECU or ECM) itself.



In diagnosing a vehicle engine, the scanner detects and reads the error code. It determines which sensor is causing the problem. There is no way for the scanner to repair and fix for good, a defective sensor it detects. In short, the scanner "talks" to the vehicle computer and the vehicle computer "tells" the scanner what is wrong. That is all what a scanner can do.



The OBD II specification was made mandatory more for the purpose of emission testing. Actually OBD I was only named as such only after OBD II was implemented. Standardization of OBD II/obdii code reader specified the type of diagnostic connector and its pins. The electronic signaling of the system and the messaging format of diagnosis were set. It also has a list of vehicle parameters to monitor along with how to encode the data for each. Overall, the OBD II code scanner device diagnoses a vehicle according to the program it has been set to operate. It will be able to tell the diagnostic trouble codes of an engine not operating normally.