diagnostic
Standard or generic fault codes encompass a set of codes universal across all manufacturers.
Known as Data Trouble Codes (DTC), this list of faults has been established to enable any diagnostic tool to interpret and decipher them. These codes adhere to a uniform format illustrated below
The classification of Diagnostic Trouble Codes (DTC) is structured as follows:
P: Powertrain (comprising the engine and gearbox)
C: Chassis
B: Body
U: User network
The first digit distinguishes between generic and manufacturer-specific codes (highlighted in green):
0: Generic fault
1: Manufacturer-specific fault
Manufacturers have the flexibility to supplement the standard OBD codes with proprietary codes as needed.
The last three digits represent a sequential number (indicated in red).
In some cases, these digits may be hexadecimal (ranging from 0 to 9 and A to F). Within the P family codes, subcategories are defined based on the first digit, as exemplified by the following breakdown:
0, 1, and 2: related to the air/fuel mixture
3: associated with the ignition system
4: involved in auxiliary emissions monitoring
5: pertaining to engine idling
6: concerning the onboard computer and ancillary outputs
7, 8, and 9: dealing with transmission (gearbox) issues
A, B, and C: specific to hybrid propulsion
These OBD codes adhere to the standards set by SAE J2012 and ISO 15031-6, encompassing approximately 11,000 defined codes in the latest versions available.