OBD II System Codes
The OBD II system monitors different areas of the vehicle. If a problem or conflict is detected, the system illuminates the MIL and sets a code in the PCM's memory. An OBD II code is an alphanumeric code containing a letter as its first digit, followed by a series of numbers. Let's have a closer look at the meaning of these digits.
1. The first digit uses an acronym to indicate the code's origin.
- P indicates the powertrain.
- B indicates the body.
- C indicates the chassis.
- U indicates the network.
2. The second digit (0) indicates whether this is a generic (SAE) code or (1) for a manufacturer specific code.
3. The third digit indicates the area of the vehicle at fault. A 3 indicates an ignition system misfire; a 7 would indicate a problem with the transmission. There are several.
4. Both the fourth and fifth digits (01) indicate the specific area. The code in the illustration indicates a misfire with the (01) #1 cylinder.