SPN 219 FMI 0Coolant
Engine Coolant Temperature - Intake Manifold
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Connector Pinout — in guided session
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Overview
Fault Code
SPN 219 / FMI 0
Category
Coolant
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: Intake manifold coolant temperature sensor is threaded into the intake manifold or coolant crossover passage, typically on the engine top or front side.
Common Symptoms
- Engine coolant temperature warning lamp illuminated
- High temperature derate active
- Reduced engine power or torque limiting
- Engine fan running continuously at high speed
- Actual coolant temperature reading abnormally high on dash
- Poor cab heating performance despite high temperature reading
- Check engine light active
Root Causes
- Coolant temperature sensor failed or drifted high (out-of-range high reading)
- Low coolant level causing inadequate cooling and genuine overtemperature condition
- Thermostat stuck closed or partially closed restricting coolant flow
- Clogged or restricted radiator reducing heat rejection capacity
- Cooling fan clutch or electric fan failure reducing airflow across radiator
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Derate Behavior
Power Derate
No
Mileage / Regen Notes
SPN 219 FMI 0 (data valid but above normal operating range) will typically inhibit active DPF regeneration to prevent additional thermal loading; sustained high coolant temp may also trigger engine derate to protect the engine.
System Interactions
SPN 219 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.
Related Faults in This Category
OEM System Resources
ASE Training Resources
Diagnostic Engine v7.0
Related Diagnostic Articles
Deep-dive diagnostic page: SPN 219 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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