Detroit Diesel DD13 Fault Codes

Complete diagnostic trouble code reference for the Detroit Diesel DD13 heavy-duty diesel engine. 2 fault codes • Protocols: J1939

🔧 Engine Context: The Detroit DD series is the backbone of the Freightliner fleet. The DD15 is the 14.8-liter engine for long-haul operations, while the 12.8-liter DD13 serves regional applications. Both use Detroit's Amplified Common Rail (ACR) fuel system and BlueTec SCR aftertreatment. Common fault codes include ECM communication issues (SPN 625), SCR system malfunctions (SPN 520605), and DEF system failures.

SPN 4342 FMI 4

NOx Sensor Outlet

Component: NOx Sensor (Outlet) / Wiring • J1939 SPN:4342 FMI:4

🟠 CHECK SOON

SPN 3226 FMI 9

DOC Inlet Temperature Sensor

Component: Diesel Oxidation Catalyst (DOC) Inlet Temp Sensor • J1939 SPN:3226 FMI:9

🟠 CHECK SOON

Engine Series Coverage: Detroit Diesel DD13 engine specifications and fault codes sourced from SAE J1939/J1587 public standards and OEM technical service documentation. Last reviewed 2026-07-06T15:05:01Z.