A list may also be found on-line here: obd 2 codes list.
Most OBDII diagnostic scanners will come with a code library of specific code meanings. The list of all these sections is long, but you can see how the final “04” in our example points to a misfire in cylinder number four. The fourth and fifth numbers of the code correspond to the section of the system causing the trouble. It is a generic code for trouble with the ignition system or a misfire. So our example trouble code P0304 indicates a problem in the powertrain. The third number corresponds to the sub-system where the problem lies.Ģ = Fuel and Air Metering (injector circuit malfunction only)ĥ = Vehicle Speed Control and Idle Control System The second digit corresponds to the type of code, whether it is the generic standard applying to all OBDII-compliant vehicles, or a manufacturer-specific code.Ģ = Includes both generic and manufacturer-specific codesģ = Includes both generic and manufacturer-specific codes There is never a letter “O” in the OBDII diagnostic code. The first digit is a letter corresponding to the main system causing the trouble code: What you get is a five-digit alpha-numeric code such as “P0304”. When you retrieve the information from the computer via an OBDII diagnostic scanner, it doesn’t tell you the problem directly, such as “timing too slow” or “misfire in cylinder number four”. The computer has assigned a trouble code to the problem and turned on the trouble light – technically called the Malfunction Indicator Lamp (MIL). The “check engine” or “service engine soon” light is the signal that there is a problem with the vehicle’s emissions. These as well as everything in the vehicle having to do with engine performance and emissions control are continuously monitored by the vehicle’s on-board computer system. Its basic components are the catalytic converter and strategically-placed oxygen sensors. The OBD2 system is primarily for emissions control. from 1996 to the present, domestic and imports. The “II” is the next generation of emissions standards and codes for all vehicles sold in the U.S. The “OBD” of OBDII – sometimes written OBD-II or just plain OBD2 – stands for On-Board Diagnostics. You’ve hooked up your scanner to the vehicle computer and retrieved the OBDII diagnostic code.
When the “check engine” or “service engine soon” light comes on, it doesn’t tell you what or where the trouble is, only that there’s trouble.