Case IH 19071 – Engine Control Unit (ECU): SCR catalyst efficiency lower than first NOx production threshold level.

The Selective Catalytic Reduction (SCR) system is failing to reduce Nitrogen Oxide (NOx) emissions to the required legal limits. While this can indicate a degraded SCR catalyst, it is frequently triggered by a failed NOx sensor giving false readings.

• Tier 4b
• 240 Series Axial-Flow Combines (5140, 6140, 7140, 7240, 8240, 9240)
• Magnum series (180, 200, 220, 240, 250, 280, 310, 340, 370, 380)
• Puma series (150, 165, 160 CVT)
• Steiger series
• T7 Series
• Patriot (2250, 3240, 3340, 4440)
• Titan (3030, 3040, 3540, 4040, 4540)
• STM N Series Loaders
• F-Series wheel loaders

1. 1

   Check DEF quality to ensure the Diesel Exhaust Fluid is not contaminated, crystallized, or diluted

2. 2

   Inspect the DEF dosing system, including the pump, lines, and dosing injector for blockages, leaks, or crystallization buildup

3. 3

   Check for exhaust leaks in the piping upstream of the SCR catalyst

4. 4

   Test upstream and downstream NOx sensors for plausibility, physical damage, or soot contamination, as Service Bulletin 2017-100 CIH N SB points to multiple NOx sensor failures causing this code

1. 1

   Address Fluid Issues

   If DEF is contaminated, drain the DEF tank, flush the system, and refill with fresh, approved DEF.

2. 2

   Clean the Doser

   Remove and clean the DEF dosing valve/injector if crystallization is present.

3. 3

   Replace the NOx Sensor

   If diagnostics or the service bulletin point to a failed sensor (highly common for code 19071), locate the faulty NOx sensor (usually the downstream sensor behind the catalyst) and disconnect the wiring harness.

4. 4

   Install New Sensor

   Remove the old sensor from the exhaust pipe and install the new OEM replacement.

5. 5

   Clear Codes

   Use a diagnostic scan tool to clear the DTC 19071 fault code.

6. 6

   System Reset/Regen

   Perform an SCR system test or forced regeneration to allow the ECU to verify that the SCR catalyst efficiency is back within the normal threshold and to clear any engine derate conditions.