Case IH F-5846-31 - ECU – Engine Control Unit (ECU): Engine Protection: Torque limitation caused by performance limiter

This is an informational fault code indicating that the engine control module has actively limited engine torque (derated the engine) because of an underlying emissions failure—specifically, excessively high NOx emissions lasting for longer than 60 seconds.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect series
• Case IH Puma series
• Case IH 240 Series Combines
• Case N-Series Loaders / TLBs

1. 1

   Scan for Primary Faults: Connect the Case IH Electronic Service Tool (EST) and read all active and stored fault codes in the ECU. Look for codes related to the SCR catalyst, DEF dosing system, or NOx sensors (e.g., 3521, 3528, 3529, 3530).

2. 2

   Check DEF Quality: Ensure the Diesel Exhaust Fluid (DEF) is not contaminated or diluted.

3. 3

   Inspect the DEF Dosing System: Run a dosing test via the service tool to verify the DEF pump/doser is building pressure and injecting fluid properly.

4. 4

   Monitor NOx Sensors: Check the upstream and downstream NOx sensor readings for plausibility. A failed sensor will falsely report high NOx, triggering the derate.

1. 1

   Address the Root Cause

   Repair or replace the component identified in your diagnostic checks (e.g., replace a failed NOx sensor or clogged DEF doser).

2. 2

   Clear the Fault Codes

   Use the dealer service tool to clear the primary emissions codes.

3. 3

   Reset the Inducement System

   Depending on how long the machine was operated in a derated state, the inducement system may be locked. You may need to navigate to the "Engine Restart Counter Reset" screen on the service tool to unlock the ECU.

4. 4

   Perform a Validation Run

   Run the engine under load to ensure the SCR system reaches operating temperature and verify that the F-5846-31 derate code does not return.