What are the symptoms of SPN 1324 FMI 13?

Rough idle or engine vibration. Reduced engine power and acceleration. Excessive white or black smoke from exhaust. Increased fuel consumption. Check engine light illuminated. Engine runs poorly under load

What causes SPN 1324 FMI 13?

Injector calibration code (IQA/trim code) not programmed or incorrectly entered into ECM for cylinder 2. Replacement injector installed without programming new calibration trim code. Fuel injector mechanical wear or internal leakage causing delivery deviation beyond calibration range. ECM software not updated after injector replacement. Contaminated or degraded fuel affecting injector spray pattern and combustion balance. Low cylinder compression reducing combustion efficiency beyond compensation range. Faulty or intermittent injector electrical connection causing inconsistent fueling

How do I diagnose SPN 1324 FMI 13?

Full step-by-step DVOM tests, electrical procedures, and connector pinout data for SPN 1324 FMI 13 are available inside the AI Diesel Tech guided diagnostic session. The AI walks you through every test — one step at a time.

SPN 1324 FMI 13Engine Protection

Misfire Cylinder 2 - Out of Calibration

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Overview

Fault Code

SPN 1324 / FMI 13

Common Symptoms

Rough idle or engine vibration
Reduced engine power and acceleration
Excessive white or black smoke from exhaust
Increased fuel consumption
Check engine light illuminated
Engine runs poorly under load

Root Causes

Injector calibration code (IQA/trim code) not programmed or incorrectly entered into ECM for cylinder 2
Replacement injector installed without programming new calibration trim code
Fuel injector mechanical wear or internal leakage causing delivery deviation beyond calibration range
ECM software not updated after injector replacement
Contaminated or degraded fuel affecting injector spray pattern and combustion balance
Low cylinder compression reducing combustion efficiency beyond compensation range
Faulty or intermittent injector electrical connection causing inconsistent fueling

Full step-by-step tests, DVOM guidance, and pinout data are available inside the AI Diesel Tech diagnostic session.

AI walks you through every test — one step at a time. Plans start at $12.95/mo.

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Derate Behavior

Power Derate

Yes

Mileage / Regen Notes

Active and parked DPF regeneration may be inhibited or suspended when a misfire fault is active to prevent unburned fuel from entering the aftertreatment system and causing DPF or DOC damage. Regen will typically remain blocked until the misfire fault is resolved and cleared.

System Interactions

SPN 1324 FMI 13 interacts with the following systems and may trigger cascading faults if not resolved promptly.

ECM communication — J1939 network faults can affect all connected modules

Engine protection — ECM may trigger derate to prevent damage

Aftertreatment — engine protection derates can affect regen strategy

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

SPN 1569-31Engine Protection Derate SPN 100-1Oil Pressure Low SPN 190-0Engine Speed High SPN 111-4Coolant Level Sensor Low

OEM System Resources

Cummins Fault Codes Detroit Diesel Fault Codes PACCAR Fault Codes Volvo Fault Codes Freightliner Fault Codes Mack Fault Codes

ASE Training Resources

Why ASE Certification Matters How ASE Tests Work ASE Study Tips ASE vs AI Diesel Tech Certification Paths Get Started with ASE

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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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