Case IH 3611 (F-4090-00) - ECU – Engine Control Module (ECM): Catalyst efficiency lower than first NOx production threshold level

The Selective Catalytic Reduction (SCR) system is not reducing Nitrogen Oxide (NOx) emissions efficiently enough to meet the 'Level 1' emissions threshold. This is an early warning fault that occurs prior to code 3612 and will eventually lead to engine torque derate (inducement).

• VESTRUM CVX
• Magnum (180-370)
• Puma (130-230)
• Steiger/Quadtrac (350-600)
• Farmall
• Axial-Flow 130, 230, and 240 series (e.g., 5130, 7130, 7230, 8230, 9230)
• Patriot (2240, 2250, 4430)
• Titan
• Case F-Series Wheel Loaders (521F, 621F, 721F, 921F)
• N-Series TLBs

1. 1

   Check exhaust temperatures to ensure they reach a minimum of 232°C (450°F) for proper SCR catalyst function

2. 2

   Use the CNH EST to check for NOx sensor plausibility faults (e.g., DTC-319E/SPN-12702 or DTC-E98E/SPN-59790)

3. 3

   Monitor DEF system dosing pressure while running; it should maintain approximately 72 psi (5 bar)

4. 4

   Inspect Diesel Exhaust Fluid (DEF) quality to ensure it is not degraded, contaminated, or diluted

5. 5

   Inspect the main DEF dosing module filter cartridge for clogs or crystallization

1. 1

   Perform a Heavy Load Run

   If the tractor or combine has been idling or operating under light loads, run the machine under a heavy load to increase exhaust temperatures above 232°C (450°F). This will often burn off deposits, restore catalyst efficiency, and clear the code naturally.

2. 2

   Replace the DEF Filter

   If dosing pressure is low or the filter is visibly restricted, replace the DEF dosing module filter cartridge.

3. 3

   Flush the DEF System

   If DEF contamination is suspected, drain the tank, flush the system, and refill with fresh, high-quality DEF.

4. 4

   Perform a UDST

   Run a Urea Dosing System Test (UDST) using the CNH EST diagnostic laptop to verify the dosing module is injecting the correct amount of fluid.

5. 5

   Replace NOx Sensors

   If the UDST passes, DEF quality is good, and temperatures are high but the code persists, replace the upstream and/or downstream NOx sensors.

6. 6

   Reset Inducement

   Because this fault causes an emissions inducement (derate), you must use the diagnostic tool to perform an 'Inducement Unlock / Counter Reset' once the physical repair is resolved.