Pollutants Codes - Decoding the OBD2 Diagnostic Code

If your "check engine" or "service engine soon" light occurs, it won't inform you what or where the the issue here is, that there's trouble. You've connected your scanner towards vehicle computer and retrieved the OBD2 diagnostic code. Precisely what does it mean?

The "OBD" of OBD2 - sometimes written OBD-II or merely plain OBD2 - represents On-Board Diagnostics. The "II" may be the next generation of emissions standards and codes for many vehicles bought from the U.S. from 1996 to the present, domestic and imports.

The OBD2 strategy is primarily for emissions control. Its basic components are classified as the catalytic converter and strategically-placed oxygen sensors. These along with everything in the car to do with engine performance and emissions control are continuously monitored because of the vehicle's on-board automatic data processing system.

The "check engine" or "service engine soon" light would be the signal that there is a downside to the vehicle's emissions. Laptop computer has assigned a trouble code for the problem and started up the effort light - technically referred to as Malfunction Indicator Lamp (MIL).

Whenever you retrieve the knowledge from your computer via an OBD2 diagnostic scanner, this doesn't happen show you the problem directly, like "timing too slow" or "misfire in cylinder number four". What you get is often a five-digit alpha-numeric code including "P0304".

The first digit can be a letter corresponding for the main system creating the trouble code:

B = Body

C = Chassis

P = Powertrain

U = Network

The next four digits are extremely numbers. There is certainly never instructions "O" from the OBD2 diagnostic code. It does not take numeric digit zero ("0").

The next digit corresponds to the sort of code, unique the generic standard signing up to all OBD2-compliant vehicles, or maybe a manufacturer-specific code.

0 = Generic codes

1 = Manufacturer-specific codes

2 = Includes both generic and manufacturer-specific codes

3 = Includes both generic and manufacturer-specific codes

The third number corresponds towards the sub-system the place that the problem lies.

1 = Fuel and Air Metering

2 = Fuel and Air Metering (injector circuit malfunction only)

3 = Ignition System or Misfire

4 = Auxiliary Emission Control System

5 = Vehicle Speed Control and Idle Control System

6 = Computer Output Circuits

7 = Transmission

8 = Transmission

So our example trouble code P0304 indicates a problem within the powertrain. It is a generic code for trouble with the ignition or maybe a misfire.

The fourth and fifth variety of the code match the area of the system resulting in the trouble. The list of these sections is long, nevertheless , you are able to see how a final "04" in your example points to some misfire in cylinder number four.

Most OBD2 diagnostic scanners includes a code library of specific code meanings. A list will also be entirely on-line by Googling "obd2 codes list".

You can sometimes discover a mention of "Bank 1" or "Bank 2" inside code explanation. These banks usually are intended for "V-type" engines. Bank 1 refers to the side in the engine while using the number one cylinder (odd-numbered cylinders). Bank 2 refers back to the side with the engine while using number 2 cylinder (even-numbered cylinders).

A misfire is really a "one-trip" or "type A" problem that by itself will not start up the MIL unless it really is severe enough to damage the catalytic converter. A severe misfire won't first turn on the MIL but will signal it to flash at one-second intervals.

Other problems tend to be "two-trip" or "type B" problems. If the computer first detects a 2-trip problem, it stores the effort code as "pending". If about the next driving trip the situation has gone by, the pending code is erased. But if the concern is still there on consecutive trips, laptop will start the MIL, alerting the motive force into a problem.

The MIL could be persistent. Once on, it's going to continue to prior to the concern is resolved for three driving trips. However, though the light might have to go out, the codes stop in laptop memory for 40-80 trips according to the problem.

Trouble codes remaining within the memory will result in a failed emissions inspection regardless of if the "check engine" light is on you aren't.

Certainly, your diagnostic scanner can make off the MIL and erase the codes through the computer's memory. It will not do much good, however, if the problem recurs after two driving trips and regenerates the problem codes. The info on the scanner ought to be helpful to locate and repair the problem, not merely shut off the MIL and erase the codes.