Standardized trouble codes SAE J 2012 (Diagnostic Trouble Codes)
Diagnostic Trouble Codes that are monitored by the engine control module are standardized, which means that all manufacturers must use the same Diagnostic Trouble Codes.
The Diagnostic Trouble Code (DTC) is always a 5-digit alphanumeric value, example "P0100 ".
All PO xxx- codes are standardized codes. However each manufacturer can use other DTCs in addition to the standardized codes. This applies when the manufacturer integrated additional functions in the control module that can be diagnosed and that exceed the law. These codes are identified as "P1 xxx", for example "P1100 ".
The first digit of a code (letter) identifies the system that the code has set. There are 4 systems:
- B for body
- C drive train
- P for engine
- U for future systems.
For OBD II only the P- Code is required.
The second digit identifies the generic code (P O xxx), or the manufacturer code (P1 xxx).
The third digit identifies the major subassembly where a malfunction occurred
These are:
The fourth and fifth digit is the identification of the subassembly or system.