Case IH 19187 (DTC 11CE) - ECU – Engine Control Unit (ECU / EDC): Upstream NOx sensor self-diagnosis result is higher than the limit.

This code indicates that the upstream Nitrogen Oxide (NOx) sensor (located before the SCR catalyst) has failed its internal self-diagnostic check, reporting a value that exceeds the maximum allowable threshold. The sensor monitors the NOx content in the exhaust gases to optimize exhaust emissions and fuel economy via the Diesel Exhaust Fluid (DEF) system.

• MAXXUM T4E
• 240 Series Axial-Flow (5140, 6140, 7140, 7240, 8240, 9240)
• Magnum (180, 200, 220, 240, 250, 280, 310, 340, 380)
• Puma (150, 150 CVT, 165, 165 CVT, 185, 200, 220)
• Maxxum
• Farmall
• Steiger 4WD series
• Patriot (2250, 3240, 3340, 4440)
• Titan (3040, 3540, 4040, 4540)

1. 1

   Check Battery Voltage: Verify the battery, alternator, and alternator belt are functioning correctly.

2. 2

   Inspect Wiring and Connectors: Check the 5-pin MCON connector (C186) and the wiring harness leading to the upstream NOx sensor for damage, corrosion, or open/short circuits.

3. 3

   Check for Exhaust Leaks: Ensure there are no exhaust leaks prior to the NOx sensor that could skew the readings.

4. 4

   Verify DEF Quality & Dosing System: Ensure the DEF fluid is not contaminated and that the DEF dosing valve/injectors are not blocked.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and allow the exhaust system to cool completely.

2. 2

   Removal

   Locate the upstream NOx sensor on the exhaust pipe (before the catalyst). Disconnect the 5-pin electrical plug.

3. 3

   Remove Sensor

   Carefully unscrew the sensor from the exhaust pipe. Warning: Do not use an impact wrench for removal or installation, as thread damage will void part warranties.

4. 4

   Clean Port

   Clean any carbon deposits from the exhaust pipe mounting port before installing the new sensor.

5. 5

   Installation

   Thread the new NOx sensor into the exhaust pipe. Warning: Do not touch the ceramic probe with bare fingers, as oil contamination will cause premature failure.

6. 6

   Reconnect

   Securely reconnect the 5-pin electrical harness.

7. 7

   Clear Codes & Test

   Reconnect the battery, use a diagnostic tool to clear the OBD fault codes, and perform a driving cycle / functional test (bringing exhaust temps above 270ºC) to verify SCR operation and ensure the code does not return.