New Holland 3931 – Engine Control Unit (ECU) or Dosing Control Unit (DCU): Info: SCR Inducement: Warning Block 4 activated

This is an informational fault code indicating that the Selective Catalytic Reduction (SCR) system has entered a specific inducement level (Warning Block 4). The engine control system initiates an inducement (performance limitation) because a primary emissions-related fault has been detected and not corrected.

• T6 series tractors
• T7 series tractors
• T8 series tractors
• T9 series tractors
• CX combines

1. 1

   Scan for primary fault codes using an Electronic Service Tool (EST) to identify the root cause (e.g., NOx sensor failure, DEF pressure issue, DEF quality issue).

2. 2

   Check DEF level and quality to ensure the tank is full and the fluid is not contaminated, diluted, or expired (concentration should be approximately 32.5%).

3. 3

   Inspect the DEF dosing system for leaks, blockages, or damaged wiring in the DEF pump, lines, and injector.

4. 4

   Check NOx sensors by inspecting the wiring and voltage, ensuring the sensor is receiving 24V and has a proper ground.

5. 5

   Inspect the CAN network to verify that all connectors to the ECU and DCU are not damaged, are properly connected, and that connector locks are intact.

1. 1

   Diagnose and Repair the Primary Fault

   Address the root cause identified during the diagnostic checks. This may involve draining and refilling the DEF tank with fresh fluid, replacing a faulty NOx sensor, or replacing a clogged DEF filter/failed DEF pump.

2. 2

   Clear Fault Codes

   Once the physical repair is complete, clear the primary fault code using the EST.

3. 3

   Perform an SCR Inducement Reset

   Use the EST to perform an 'SCR Inducement Reset' (sometimes found under 'Engine Emissions Operator Inducement Service Mode Override' in the diagnostic tests). This clears the inducement counter and restores normal engine performance.

4. 4

   System Validation

   In some cases, a manual regeneration or running the engine under load may be required to allow the system to validate the repair and fully clear the inducement state.