Case IH 19071 (DTC 2DDA) - ECU – Engine ECU: SCR catalyst efficiency lower than first NOx production threshold level

The Selective Catalytic Reduction (SCR) system is failing to reduce Nitrogen Oxides (NOx) emissions efficiently enough to meet the first required threshold. This typically indicates that the SCR catalyst is degraded, the Diesel Exhaust Fluid (DEF/AdBlue) is of poor quality, or the NOx sensors are providing inaccurate readings.

• MAXXUM T4E
• 240 Series Axial-Flow (5140, 6140, 7140, 7240, 8240, 9240)
• Magnum (180, 200, 220, 240, 250, 280, 310, 340)
• Puma (150, 165)
• Maxxum
• Farmall series
• Patriot (2250, 3240, 3340, 4440)
• Titan (3040, 3540, 4040, 4540)
• Case N-Series TLBs

1. 1

   Check for related NOx sensor faults (DTC-319E/SPN-12702 or DTC-E98E/SPN-59790) using a diagnostic tool

2. 2

   Check DEF/AdBlue quality for contamination or dilution, and look for active DEF quality faults (e.g., SCR 011 Active)

3. 3

   Inspect the DEF quality sensor for damage or chemical reactions caused by inadequate fluid quality

1. 1

   Address Sensor Faults First

   If DTC-319E or DTC-E98E are present, replace the faulty NOx sensor(s) first, clear the codes, and retest.

2. 2

   Drain and Refill DEF

   If DEF quality is questionable, drain the DEF/AdBlue tank completely, clean it, and refill it with approved, high-quality DEF/AdBlue.

3. 3

   Replace the DEF Quality Sensor

   If no other NOx sensor faults are present and the fluid is known to be good, the issue is often a failed DEF urea quality sensor. Replace the DEF/AdBlue urea quality sensor (DEF Head Unit).

4. 4

   Retest the Machine

   Clear the fault codes and run the machine under load to ensure the SCR system reaches operating temperature.

5. 5

   Escalation

   If the fault is still not resolved after replacing the DEF quality sensor and verifying NOx sensor operation, the SCR catalyst itself may be permanently damaged or face functional obsolescence and require replacement. Escalate to a dealer service department. Note: Do not turn off the engine, drive the machine, or increase the load on the machine while active severe SCR derates are occurring to avoid further damage to the catalyst.