Cummins Fault Code

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SPN: 3582 FMI: 2

SCR System Fault / Derate.

System

Aftertreatment

Symptom

SCR System Fault / Derate.

Diagnosis & fix steps

LOGIC: SCR Catalyst Intake Temperature - Data Erratic. ACTION: Inspect the SCR temperature sensor harness for rubbing. Swap sensor with the SCR Outlet sensor to see if the fault follows.

Red Seal field insights

Specs: Voltage should fluctuate between 0.5V and 4.5V. RED SEAL FIX: This is often a "correlation" error. If the sensors differ by more than 25°C at dead-cold (engine off 8+ hours), the ECM flags an FMI 2.

Same code keeps coming back?

That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.

Book an uptime review

Read before you touch anything

  • This is general reference information, not a repair manual. It is for trained, qualified technicians.
  • Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
  • Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
  • You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
  • Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.

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