Case IH 19797 – Engine Control Module (ECM) or Dosing Control Unit (DCU): SCR Inducement: Level 1 (Torque reduction), triggered by DEF/AdBlue quality fault.

The emissions system has detected that the Diesel Exhaust Fluid (DEF) in the tank does not meet the required quality or concentration standards (typically 32.5% urea). Because the Selective Catalytic Reduction (SCR) system cannot properly reduce NOx emissions with poor-quality fluid, the system automatically enforces a Level 1 engine derate (torque reduction) to protect the environment and comply with emissions regulations.

• Tier 4b
• 240 Series Axial-Flow Combines
• Farmall 40, 45, 50, and 110A Tractors
• T7 Series Tractors
• SV340B and TR340 Compact Track Loaders

1. 1

   Test the DEF Fluid: Use a DEF refractometer to test the fluid currently in the tank. It must read exactly 32.5% urea.

2. 2

   Inspect for Contamination: Visually check the DEF for cloudiness, dirt, water, or diesel fuel contamination, which can cause chemical reactions that damage the sending unit.

3. 3

   Check for Related Codes: Look for associated codes that might pinpoint a hardware failure rather than just bad fluid (e.g., DTC 19161 for internal failure, or 19798/19799 for escalating inducement levels).

4. 4

   Inspect the Sensor and Wiring: Check the DEF Head Unit / Quality Sensor wiring harness for corrosion, moisture, or physical damage caused by extreme temperatures or vibrations.

1. 1

   Drain the Tank

   If the DEF fluid tests out of specification or is contaminated, place a clean drain pan under the DEF tank and completely drain the fluid.

2. 2

   Flush the System

   Flush the DEF tank with distilled water or fresh DEF to remove any remaining contaminants, debris, or crystallized urea.

3. 3

   Replace the DEF Filter

   Remove the old DEF filter and install a new one to ensure no contaminated fluid remains trapped in the dosing lines.

4. 4

   Replace the Sensor (If Faulty)

   If the fluid was clean but the sensor failed internally (or if contamination permanently damaged the sensor probes), remove the DEF head unit assembly from the tank and install a new OEM replacement.

5. 5

   Refill

   Refill the tank with fresh, high-quality DEF (32.5% urea).

6. 6

   Clear Codes and Validate

   Connect your diagnostic tool to clear the fault codes. You must then perform an "Inducement Validation Restart" (a full power restart mode activated specifically for inducement validation) to allow the system to verify the new DEF quality and lift the Level 1 torque reduction.