SPN 164 FMI 2Fuel SystemHigh
Injection Control Pressure — Data Erratic, Intermittent or Incorrect
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Overview
Fault Code
SPN 164 / FMI 2
Category
Fuel System
Fault Type
sensor
FMI Category
data erratic
Severity
High
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
No
Component Location: ICP sensor mounted on high-pressure oil rail — typically top of engine near valve cover. IPR valve on high-pressure oil pump, rear of engine.
Common Symptoms
- Hard start or extended crank time
- Engine misfires or rough running
- Low power under load
- ICP reading erratic or jumping in live data
- Possible white or black smoke at startup
Root Causes
- ICP sensor failure — internal contamination or drift
- ICP sensor wiring — intermittent open or short
- High-pressure oil system leak reducing ICP
- IPR (Injection Pressure Regulator) valve sticking or worn
- High-pressure oil pump worn — unable to maintain stable ICP
- Oil aeration — air in high-pressure oil circuit
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Derate Behavior
Power Derate
Yes
Mileage / Regen Notes
High frequency 250k–500k miles. ICP sensor lifespan typically 200k–350k miles.
System Interactions
SPN 164 FMI 2 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 4021892 — ICP Sensor Replacement and High-Pressure Oil System Inspection
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
ISX/X15: ICP sensor is a known wear item at 300k+ miles. Always inspect o-ring on sensor body during replacement.
Detroit
DD15: Uses different high-pressure fuel rail system — confirm SPN 164 is ICP not fuel rail pressure on DD platform.
PACCAR
MX-13: Check IPR valve screen for debris before condemning pump.
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OEM System Resources
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 164 FMI 2 — 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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