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Cummins Fault Codes — Complete Guide

Cummins SPN/FMI codes cover ISX15, X15, ISB6.7 and 4 more platforms. This hub lists 144 diagnostic pages with symptoms, ranked causes, scan-tool steps, and 2026 repair costs — use INSITE, DiagnosticLink, or EST depending on your engine family.

By Professional Diesel Repair TeamPublished: January 2026Last updated: September 2026

How We Tested and Verified

Cummins fault code definitions cross-checked against SAE J1939-71 and Cummins OEM service bulletins. Diagnostic tips validated by field technicians September 2026.

Cummins Engine Platforms

Cummins engines covered on this site include: ISX15, X15, ISB6.7, ISC8.3, B6.7, L9, X12. Diagnostic procedures vary by platform — always verify against your specific engine serial number and calibration.

Most Common Cummins Fault Codes

CodeComponentSeverityDefinition
SPN 0606 FMI N/AECM/PCMCriticalECM/PCM Processor Fault
SPN P0093 FMI N/AFuel System Large Leak DetectedCriticalFuel System Large Leak Detected
SPN P0217 FMI N/AEngine Cooling SystemCriticalEngine Over Temperature Condition
SPN P0217 FMI N/AEngine Cooling SystemCriticalEngine Over Temperature Condition
SPN P0217 FMI N/AEngine Cooling SystemCriticalEngine Over Temperature Condition
SPN P0524 FMI N/AEngine Oil PressureCriticalEngine Oil Pressure Too Low
SPN 100 FMI 1Engine Oil Pressure Sensor / Oil Pressure CircuitCriticalEngine Oil Pressure - Data Valid But Below Normal Operating Range - Moderately Severe Level
SPN 100 FMI 18Engine Oil Pressure SensorCriticalEngine Oil Pressure - Data Valid But Below Normal Operational Range - Moderately Severe Level
SPN 1209 FMI 0Exhaust Gas Pressure Sensor (Exhaust Backpressure)CriticalEngine Exhaust Gas Pressure - Data Valid But Above Normal Operating Range - Most Severe Level
SPN 1569 FMI 31Engine Protection ShutdownCriticalEngine Protection System - Condition Exists
SPN 157 FMI 16Engine Fuel Rail PressureCriticalFuel Rail Pressure - Data Valid But Above Normal Operating Range
SPN 1761 FMI 1DEF Tank Level SensorCriticalAftertreatment 1 Diesel Exhaust Fluid Tank Level - Data Valid But Below Normal Operating Range - Most Severe Level
SPN 190 FMI 0Engine Speed Sensor CircuitCriticalEngine Speed - Data Valid But Above Normal Operational Range
SPN 190 FMI 2Engine Speed SensorCriticalEngine Speed - Data Erratic, Intermittent, Or Incorrect
SPN 2659 FMI 18DEF Dosing UnitCriticalDEF Dosing Unit - Data Valid But Below Normal Operating Range
SPN 5246 FMI 15SCR InducementCriticalDiesel Exhaust Fluid Quality - Data Valid But Above Normal Operating Range - Moderately Severe Level
SPN 5246 FMI 16SCR InducementCriticalAftertreatment SCR Operator Inducement - Data Valid But Above Normal Operating Range - Severe
SPN 629 FMI 12Electronic Control Module (ECM)CriticalElectronic Control Module - Critical Internal Failure, Bad Intelligent Device or Component
SPN 0191 FMI N/AFuel Rail Pressure SensorHighFuel Rail Pressure Sensor Circuit Range/Performance
SPN 0192 FMI N/AFuel Rail Pressure SensorHighFuel Rail Pressure Sensor Circuit Low Input

Cummins-Specific Diagnostic Tips

  • Use Cummins INSITE for bi-directional control of VGT, DEF doser, and DPF regen.
  • Freeze-frame data on Cummins stacks SPN 1569 protection codes — always read the trigger fault first.
  • Check calibration IDs after ECM replacement; incorrect cal causes ghost aftertreatment codes.

All Cummins Fault Codes (144)

SPN 0102 FMI N/A

Mass Air Flow Sensor

SPN 0171 FMI N/A

Fuel System

SPN 0191 FMI N/A

Fuel Rail Pressure Sensor

SPN 0192 FMI N/A

Fuel Rail Pressure Sensor

SPN 0202 FMI N/A

Injector Circuit Cylinder 2

SPN 0216 FMI N/A

Injection Timing Control

SPN 0380 FMI N/A

Glow Plug/Heater Circuit

SPN 0473 FMI N/A

Exhaust Pressure Sensor

SPN 0606 FMI N/A

ECM/PCM

SPN 2263 FMI N/A

Turbo Boost System

SPN INSITE-AT FMI N/A

Cummins INSITE Aftertreatment Diagnostics

SPN P0016 FMI N/A

Crankshaft/Camshaft Timing Correlation

SPN P0087 FMI N/A

Fuel Rail Pressure Too Low

SPN P0087 FMI N/A

Fuel Rail Pressure Too Low

SPN P0087 FMI N/A

Fuel Rail Pressure Too Low

SPN P0088 FMI N/A

Fuel Rail Pressure

SPN P0088 FMI N/A

Fuel Rail Pressure

SPN P0088 FMI N/A

Fuel Rail Pressure

SPN P0093 FMI N/A

Fuel System Large Leak Detected

SPN P00AF FMI N/A

Turbocharger Boost Control 'B' Position Exceeded Learning Limit

SPN P0101 FMI N/A

MAF Circuit Range/Performance

SPN P0116 FMI N/A

Engine Coolant Temperature Circuit

SPN P0117 FMI N/A

Engine Coolant Temperature Sensor

SPN P0183 FMI N/A

Fuel Temperature Sensor Circuit

SPN P0193 FMI N/A

Fuel Rail Pressure Sensor Circuit High Input

SPN P0193 FMI N/A

Fuel Rail Pressure Sensor Circuit High Input

SPN P0193 FMI N/A

Fuel Rail Pressure Sensor Circuit High Input

SPN P0201 FMI N/A

Fuel Injector Cylinder 1

SPN P0203 FMI N/A

Fuel Injector Circuit - Cylinder 3

SPN P0217 FMI N/A

Engine Cooling System

SPN P0217 FMI N/A

Engine Cooling System

SPN P0217 FMI N/A

Engine Cooling System

SPN P0219 FMI N/A

Engine Overspeed Condition

SPN P0234 FMI N/A

Turbocharger Boost Control

SPN P0234 FMI N/A

Turbocharger Boost Control

SPN P0234 FMI N/A

Turbocharger Boost Control

SPN P0299 FMI N/A

Turbocharger Underboost

SPN P0299 FMI N/A

Turbocharger Underboost

SPN P0299 FMI N/A

Turbocharger Underboost

SPN P0300 FMI N/A

Random/Multiple Cylinder Misfire

SPN P0335 FMI N/A

Crankshaft Position Sensor

SPN P0336 FMI N/A

Crankshaft Position Sensor Circuit

SPN P0340 FMI N/A

Camshaft Position Sensor

SPN P0341 FMI N/A

Camshaft Position Sensor Circuit

SPN P0401 FMI N/A

EGR Flow Insufficient

SPN P0401 FMI N/A

EGR Flow Insufficient

SPN P0401 FMI N/A

EGR Flow Insufficient

SPN P0402 FMI N/A

EGR System

SPN P0402 FMI N/A

EGR System

SPN P0402 FMI N/A

EGR System

SPN P0403 FMI N/A

EGR Valve Control Circuit

SPN P0470 FMI N/A

Exhaust Pressure Sensor Malfunction

SPN P0471 FMI N/A

Exhaust Pressure Sensor Performance

SPN P0472 FMI N/A

Exhaust Pressure Sensor

SPN P0500 FMI N/A

Vehicle Speed Sensor

SPN P0521 FMI N/A

Engine Oil Pressure Sensor/Switch

SPN P0523 FMI N/A

Engine Oil Pressure Sensor Circuit High

SPN P0523 FMI N/A

Engine Oil Pressure Sensor Circuit High

SPN P0523 FMI N/A

Engine Oil Pressure Sensor Circuit High

SPN P0524 FMI N/A

Engine Oil Pressure

SPN P0526 FMI N/A

Fan Speed Sensor Circuit

SPN P0562 FMI N/A

Charging System / Battery

SPN P0611 FMI N/A

Fuel Injector Control Module

SPN P0638 FMI N/A

Intake Throttle Actuator Control

SPN P0670 FMI N/A

Glow Plug Control Circuit

SPN P0670 FMI N/A

Glow Plug Control Circuit

SPN P0670 FMI N/A

Glow Plug Control Circuit

SPN P0671 FMI N/A

Glow Plug 1 Control Circuit

SPN P2002 FMI N/A

DPF Efficiency Below Threshold

SPN P2002 FMI N/A

DPF Efficiency Below Threshold

SPN P2002 FMI N/A

DPF Efficiency Below Threshold

SPN P2033 FMI N/A

Exhaust Gas Temperature Sensor - Position 2

SPN P203F FMI N/A

Reductant System Performance

SPN P2048 FMI N/A

Reductant Temperature Sensor

SPN P20E8 FMI N/A

Ram 6.7 Cummins DEF Pump System

SPN P20EE FMI N/A

SCR NOx Catalyst Efficiency

SPN P20EE FMI N/A

SCR NOx Catalyst Efficiency

SPN P20EE FMI N/A

SCR NOx Catalyst Efficiency

SPN P2262 FMI N/A

Turbocharger Boost Pressure Not Detected - Mechanical

SPN P226C FMI N/A

Turbocharger Boost Control Position Not Learned

SPN P244B FMI N/A

DPF Differential Pressure Too High

SPN P2459 FMI N/A

DPF Regeneration Frequency

SPN P2459 FMI N/A

DPF Regeneration Frequency

SPN P2459 FMI N/A

DPF Regeneration Frequency

SPN P246C FMI N/A

DEF Reductant Quality Performance

SPN 100 FMI 1

Engine Oil Pressure Sensor / Oil Pressure Circuit

SPN 100 FMI 17

Engine Oil Pressure

SPN 100 FMI 18

Engine Oil Pressure Sensor

SPN 102 FMI 3

Boost Pressure Sensor Circuit

SPN 105 FMI 0

Intake Manifold Temperature Sensor

SPN 105 FMI 4

Intake Manifold Temperature

SPN 110 FMI 16

Engine Coolant Temperature Sensor

SPN 110 FMI 3

Engine Coolant Temperature

SPN 111 FMI 3

Coolant Level

SPN 1209 FMI 0

Exhaust Gas Pressure Sensor (Exhaust Backpressure)

SPN 1381 FMI 18

Fuel Supply Pump Inlet Pressure Sensor

SPN 1381 FMI 4

Fuel Supply Pump Inlet Pressure Sensor

SPN 1382 FMI 16

Fuel Filter Differential Pressure

SPN 1569 FMI 31

Engine Protection Shutdown

SPN 157 FMI 16

Engine Fuel Rail Pressure

SPN 157 FMI 2

Fuel Rail Pressure

SPN 164 FMI 1

Injector Metering Rail 1 Pressure

SPN 168 FMI 2

Battery / ECU Power Supply Circuit

SPN 172 FMI 3

Engine Air Inlet Temperature Sensor

SPN 1761 FMI 1

DEF Tank Level Sensor

SPN 190 FMI 0

Engine Speed Sensor Circuit

SPN 190 FMI 2

Engine Speed Sensor

SPN 2659 FMI 18

DEF Dosing Unit

SPN 27 FMI 7

EGR Valve

SPN 3031 FMI 10

EGR Valve

SPN 3216 FMI 0

SCR Intake NOx Sensor

SPN 3226 FMI 0

SCR Outlet NOx Sensor

SPN 3251 FMI 0

DPF Differential Pressure

SPN 3251 FMI 16

DPF Differential Pressure

SPN 3361 FMI 9

DEF Tank Level

SPN 3362 FMI 9

DEF Tank Temperature

SPN 3363 FMI 9

EGR System

SPN 3364 FMI 9

DEF Dosing Unit

SPN 3480 FMI 1

HC Doser Fuel Supply Pressure

SPN 3509 FMI 4

5-Volt Sensor Supply Voltage 1

SPN 3719 FMI 0

DPF Ash Load

SPN 3719 FMI 16

DPF Ash Load

SPN 4334 FMI 31

SCR Catalyst Reagent Quality/Efficiency

SPN 4364 FMI 1

SCR NOx Efficiency

SPN 4364 FMI 18

SCR NOx Conversion Efficiency

SPN 4766 FMI 10

DOC Outlet Gas Temperature

SPN 4766 FMI 16

DOC Outlet Gas Temperature

SPN 512 FMI 2

Driver's Demand Engine Percent Torque

SPN 520372 FMI 16

DEF Dosing System

SPN 5246 FMI 0

SCR Inducement

SPN 5246 FMI 15

SCR Inducement

SPN 5246 FMI 16

SCR Inducement

SPN 629 FMI 12

Electronic Control Module (ECM)

SPN 636 FMI 2

Crankshaft Position Sensor

SPN 651 FMI 5

Injector Solenoid Driver Circuit - Cylinder #1

SPN 653 FMI 5

Fuel Injector Cylinder 3

SPN 654 FMI 5

Injector Cylinder 4

SPN 723 FMI 2

Transmission Output Speed

SPN 84 FMI 2

Wheel-Based Vehicle Speed Sensor

SPN 91 FMI 3

Accelerator Pedal Position

SPN 94 FMI 3

Fuel Delivery Pressure Sensor Circuit

SPN 98 FMI 1

Engine Oil Level Sensor / Oil Level Circuit

SPN VGT-CAL FMI N/A

Variable Geometry Turbo Actuator

SPN X15-TSB FMI N/A

Cummins X15 Aftertreatment System

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