SPN 144 FMI 0Air Intake
Intake Air Temperature Circuit High
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 144 / FMI 0
Category
Air Intake
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: Intake air temperature sensor is typically located in the intake manifold or air intake piping between the air filter and turbocharger inlet.
Common Symptoms
- Check engine light illuminated
- Engine derate or reduced power
- Poor cold start performance
- Excessive black smoke during acceleration
- Higher than normal fuel consumption
Root Causes
- Faulty intake air temperature sensor Open circuit in sensor wiring harness Corroded or damaged sensor connector Broken or chafed wiring to IAT sensor ECM internal fault
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Derate Behavior
Power Derate
No
System Interactions
SPN 144 FMI 0 interacts with the following systems and may trigger cascading faults if not resolved promptly.
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.
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OEM System Resources
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 144 FMI 0 — 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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