SPN 1347 FMI 7Fuel SystemHigh
Fuel Injection Control Pressure - Mechanical System Not Responding Properly
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Overview
Fault Code
SPN 1347 / FMI 7
Category
Fuel System
Fault Type
actuator
FMI Category
mechanical
Severity
High
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
No
Component Location: Fuel injection control pressure regulator (IMV) mounted on the high-pressure fuel pump - typically at the fuel pump inlet. High-pressure fuel pump location varies by OEM: Cummins X15 - rear of engine, gear-driven. Detroit DD15 - rear of engine. PACCAR MX-13 - driver side, gear-driven.
Common Symptoms
- Fuel injection control pressure not responding to ECM commands
- Engine derate active - ECM cannot control injection pressure
- Hard start or extended cranking - insufficient injection pressure
- Rough idle or misfires - injection pressure unstable
- Possible companion faults: SPN 157/18 (rail pressure low), SPN 157/3 (rail pressure sensor high)
- Fuel injection control pressure regulator not responding to commanded pressure
Root Causes
- Fuel injection control pressure regulator (IMV) failure - regulator not responding to ECM command
- IMV solenoid failure - solenoid not opening or closing on command
- High-pressure fuel pump wear - pump cannot build commanded pressure
- Fuel pressure relief valve stuck open - pressure bleeds off through relief valve
- IMV wiring fault - regulator receives command but cannot respond
- Fuel contamination - water or debris in fuel system affecting regulator operation
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Derate Behavior
Power Derate
Yes
Mileage / Regen Notes
IMV failure increases with mileage. HP pump wear increases significantly at 500k+ miles. Fuel contamination can cause failure at any mileage.
System Interactions
SPN 1347 FMI 7 interacts with the following systems and may trigger cascading faults if not resolved promptly.
Fuel rail pressure — injector timing and quantity affected
Engine power output — derate may be triggered to protect injectors
Aftertreatment regen — low fuel pressure can prevent regen completion
TSB Reference: Cummins TSB 4021756 - Fuel Injection Control Pressure Regulator Diagnosis; Detroit TSB 17-008 - Fuel Pressure Regulator Mechanical Fault
Common Diagnostic Mistakes
Replacing the sensor without verifying wiring continuity and supply voltage first.
Clearing codes without identifying and resolving the root cause — the fault will return.
Ignoring related active faults — cascading faults often share a root cause.
Skipping the connector inspection — corrosion and damaged pins are a leading cause of sensor faults.
Condemning the ECM before exhausting all wiring and component tests.
Replacing injectors without verifying fuel supply pressure — low supply pressure causes injector faults.
Ignoring fuel filter restriction — a clogged filter causes low rail pressure that mimics injector failure.
OEM Notes
Cummins
X15: IMV failure is common at high mileage. INSITE fuel pressure regulator test required. Check fuel filter service interval before condemning IMV.
Detroit
DD15: Fuel pressure relief valve failure is common on DD15 - valve sticks open causing chronic low pressure. DDDL fuel system test required.
PACCAR
MX-13: IMV solenoid failure is common at 400k+ miles. DAVIE4 fuel pressure analysis required. Check fuel quality - water contamination damages IMV.
Volvo
MP8: HP pump wear is common at 500k+ miles on MP8. PTT fuel system test required. Check lift pump output before condemning HP pump.
Related Faults in This Category
OEM System Resources
ASE Training Resources
Diagnostic Engine v7.0
Related Diagnostic Articles
Deep-dive diagnostic page: SPN 1347 FMI 7 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.
Authority References
Diagnostic procedures on this page are informed by OEM service literature and industry standards.
Cummins QuickServe OnlineOfficial Cummins service manuals, fault code lookup, and TSB database.Detroit Diesel DiagnoCentralDetroit Diesel diagnostic procedures, DDDL documentation, and service literature.PACCAR MX Engine ServicePACCAR MX-11 and MX-13 engine service documentation and DAVIE diagnostic guides.Volvo/Mack Tech ToolVolvo and Mack engine fault code reference and PTT/Tech Tool diagnostic procedures.ASE — Diesel Truck Technician CertificationNational Institute for Automotive Service Excellence — T2 Diesel Engines certification standards.EPA Aftertreatment & Emissions GuidelinesU.S. EPA heavy-duty diesel aftertreatment compliance, DPF/SCR regulations, and NOx standards.
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