DTC Decoder
Paste a code like P0301 or raw bytes from any of the three on-wire encodings:
OBD-II / SAE J2012 (2 bytes), UDS / ISO 14229 (3 bytes + status), or J1939 SPN+FMI
(4-byte DM record). Get a structural breakdown plus a plain-English description.
Descriptions are the generic SAE J2012 set; manufacturer-specific codes
decode structurally but have no public description. Runs entirely offline.
Batch: separate several codes with commas or new lines.
Auto-detect sniffs the format. A bare 4-byte value is ambiguous (UDS+status vs J1939), so both
interpretations are shown.
DTCs travel over different transports on the wire. Learn how the OBD-II / ISO-TP layer carries them in the OBD-II Explainer.