OBD Diagnostic Codes Explained

The check engine light comes on, and you can scan the vehicle’s computer and get OBD diagnostic codes. The codes don’t tell you which part is needed to replace. They just tell you that the symptom of the problem and you will need to diagnose further to determine the cause of the problem.

image of obd scan tools

The codes consist of one alphebet and 4-digit number. Without looking up the meaning of the code, you can tell some information from the alphebet and the first 2 digit.

The codes are categorized into four different types. B is for Body, C is for Chassis, P is for Powertrain, U is for Network. P-codes are responsible for check engine light. The P-codes starting with 0 are generic codes. They are standardized. It doesn’t matter which manufacturer. The code starting with 0 are the same meaning among any manufacturers. However, the P-codes starting with 1 are manufacturer specific codes or enhanced codes. These codes have a different meaning for each manufacturer. Some cheap code reader can pull out the codes but without descriptions. You will need to look up the meaning of the codes online or repair manuals.

The second digit of P-code tells you the following categories. You don’t have to memorize them, but it’s good to know that they are categorized into those systems.

  • 1 Fuel and Air Metering
  • 2 Fuel and Air Metering Injector Circuit
  • 3 Ignition System
  • 4 Emission Controls
  • 5 Vehicle Speed Controls and Idle Control
  • 6 Computer Output Circuit
  • 7 Transmission
  • 8 Transmission
image of bluedriver

Now you have a better idea of OBD diagnostic codes. You can tell which system is having the problem from the codes. Then you will have to diagnose further to narrow down the cause of the problem. An OBD scan tool called BlueDriver is a very popular OBD adapter. It is focused on vehicle diagnostics. You will get the detail of the codes and repair reports that contains possible causes and verified fixes. And it can scan enhanced codes including ABS, SRS, Transmission, TPMS, etc. With a good repair manual, you can tackle complicated OBD-related problems with confidence.

Read Also: What should you do when Check Engine Light comes on?

Leave a Reply

Your email address will not be published. Required fields are marked *