Case IH 19800 (DTC FD9F) - ECU – Engine Control Unit (ECU) / Engine Control Module (ECM): SCR Inducement: Level 1 (Torque reduction), triggered by Tampering fault.

The engine control system has detected a "Tampering fault" within the Selective Catalytic Reduction (SCR) emissions system. This is an overarching regulatory inducement (derate) code. It means the system suspects an emissions component has been disconnected, blocked, or bypassed (e.g., a blocked DEF dosing valve, a disconnected NOx sensor, a blocked EGR valve, or diesel fuel detected in the DEF tank). To force the operator to repair the emissions system, the ECU enforces a Level 1 torque reduction (engine power loss).

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• 140 Series Combines (5140, 6140, 7140)
• Magnum series (180, 200, 240, 250, 280, 310, 340)
• Steiger series
• Puma series
• Maxxum series
• Patriot series (2250, 3240, 3340, 4440)
• Titan series

1. 1

   Read all active codes to find the specific component fault that triggered the tampering logic

2. 2

   Check DEF quality for contamination, such as diesel fuel or water in the DEF tank

3. 3

   Inspect SCR components for physical tampering, disconnected wiring harnesses, or blocked lines at the DEF dosing valve, NOx sensors, and EGR valve

1. 1

   Connect Diagnostic Tool

   Connect the CNH Electronic Service Tool (EST) to the machine's diagnostic port.

2. 2

   Identify Root Cause

   Read the fault code stack. Identify the root cause fault code that triggered the "Tampering" inducement (e.g., a code for a failed NOx sensor, a blocked DEF dosing valve, or a CAN timeout error from the DEF quality sensor).

3. 3

   Perform Physical Repair

   Repair the root cause fault. This may involve replacing a faulty NOx sensor, cleaning/replacing a blocked DEF dosing valve, or draining and flushing a contaminated DEF tank.

4. 4

   Clear Codes

   Clear the root cause fault codes from the ECU.

5. 5

   Perform Inducement Validation Restart

   You cannot simply clear code 19800. Once the root cause is repaired, you must use the diagnostic tool to perform an "Inducement Validation Restart". This will temporarily trigger code 19809 (Inducement Validation Restart mode activated - full power restart for inducement validation). This step is mandatory to validate the repair to the ECU and lift the 19800 tampering derate.

6. 6

   Test Run

   Run the engine at full power to ensure the torque reduction is lifted and no SCR codes return.