Won T Restart — Possible Fault Codes

Found 3 fault codes associated with won t restart. Codes are sorted by severity — check STOP ENGINE codes first.

⚠️ 3 STOP ENGINE-level codes associated with this symptom. Do not continue driving.

SPN 639 FMI 9

J1939 CAN Bus Communication Loss

Cummins ISX15 • Component: Engine Control Module / CAN Bus • J1939

🔴 STOP ENGINE

SPN 164 FMI 18

Fuel Rail Pressure critically low

Detroit Diesel DD15 • Component: High Pressure Fuel System • J1939

🔴 STOP ENGINE

SPN 1347 FMI 7

Fuel Pump Pressurizing Assembly (HPP)

PACCAR MX-13 • Component: High Pressure Fuel Pump (HPP) • J1939

🔴 STOP ENGINE

⚠️ Diagnostic Note: Symptoms can have multiple root causes. Always verify with a diagnostic scan tool before replacing parts. The fault codes listed above are possible matches for won t restart based on SAE J1939/J1587 fault code definitions and OEM service documentation.