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Turbo Underboost — Possible Fault Codes
Found 6 fault codes associated with turbo underboost. Codes are sorted by severity — check STOP ENGINE codes first.
⚠️ 3 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
SPN 102 FMI 18
Intake Manifold Pressure critically low
Cummins ISX15 • Component: Turbocharger / Charge Air System • J1939
SPN 641 FMI 5
VGT Turbo Actuator
International A26 • Component: Variable Geometry Turbocharger (VGT) Actuator • J1939
SPN 3480 FMI 4
Intake Manifold Pressure Sensor
International A26 • Component: Intake Manifold Pressure (MAP) Sensor / Wiring • J1939
SPN 106 FMI 0
Air Filter Restriction High
International A26 • Component: Air Filter Differential Pressure Sensor / Air Intake • J1939
SPN 677 FMI 5
Turbocharger Actuator Fault
PACCAR MX-13 • Component: Turbocharger Wastegate Actuator / Turbo Control • J1939
⚠️ 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.