Case IH 19061 – Engine Control Unit (ECU) / Engine Management System (EMS): Upstream NOx sensor lambda signal deviation - NOx sensor possible removal detected.

This code indicates that the lambda (oxygen) signal from the upstream NOx sensor is deviating from expected parameters. The system detects that the sensor values are not plausible, which suggests the sensor has either failed, has a wiring issue, or has been physically removed/tampered with. The upstream NOx sensor is located before the Diesel Oxidation Catalyst (DOC) and measures the level of pollutants and unburned fuel coming directly from the engine combustion chambers.

• Tier 4b
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Magnum (180–380)
• Puma (140–240)
• Steiger 4WD & Quadtrac (370–620)
• Maxxum (115–150)
• Optum (250–300)
• Farmall (110A–140A)

1. 1

   Verify that the upstream NOx sensor is physically present in the exhaust pipe before the DOC and has not been removed or tampered with.

2. 2

   Inspect the upstream NOx sensor wiring harness and its 5-cavity connector (Connector C186) for frayed wires, melted insulation, or corrosion.

3. 3

   Inspect the exhaust manifold and piping upstream of the NOx sensor for leaks, as introducing outside air can skew the lambda readings and trigger a false code.

4. 4

   Connect a diagnostic tool to monitor the live lambda signal from the upstream NOx sensor. If the voltage is out of range or completely static while the engine is running, the sensor or its module has likely failed internally.

1. 1

   Preparation

   Park the machine on a level surface, turn off the engine, and remove the key. Crucial: Allow the exhaust system to cool completely, as the DOC and surrounding pipes operate at extremely high temperatures.

2. 2

   Disconnect the Sensor

   Locate the upstream NOx sensor module and disconnect its electrical connector from the main engine harness.

3. 3

   Remove the Sensor

   Using a specialized NOx sensor socket or a standard wrench (typically 22mm), carefully unscrew the NOx sensor probe from the exhaust pipe.

4. 4

   Install the New Sensor

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (if it does not come pre-applied from the factory). Thread the new sensor into the exhaust pipe by hand to prevent cross-threading, then tighten it to the OEM torque specification.

5. 5

   Route and Reconnect

   Secure the sensor's control module to its mounting bracket. Route the wiring away from extreme heat sources and moving parts, then plug the connector back into the harness.

6. 6

   Clear Codes

   Turn the key to the ON position, connect your diagnostic tool, and clear the 19061 / 32BE fault code. Start the engine and allow it to reach operating temperature to ensure the code does not return.