Turbo Underboost — Possible Fault Codes

Found 3 fault codes associated with turbo underboost. Codes are sorted by severity — check STOP ENGINE codes first.

⚠️ 2 STOP ENGINE-level codes associated with this symptom. Do not continue driving.

SPN 1569 FMI 31

Engine Protection Torque Derate

Cummins ISX15 • Component: Engine Control Module (ECM) • J1939

🔴 STOP ENGINE

SPN 102 FMI 18

Intake Manifold Pressure critically low

Cummins ISX15 • Component: Turbocharger / Charge Air System • J1939

🔴 STOP ENGINE

SPN 641 FMI 5

VGT Turbo Actuator

International A26 • Component: Variable Geometry Turbocharger (VGT) Actuator • J1939

🟡 CHECK AT NEXT STOP

⚠️ 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 turbo underboost based on SAE J1939/J1587 fault code definitions and OEM service documentation.