Case IH 19059 (F-3224-06) – Engine Control Unit (ECU / ECM): Upstream NOx sensor internal failure (Short Circuit Error)

This code indicates that the Engine Control Unit has detected an internal short circuit in the upstream Nitrogen Oxide (NOx) sensor.

• VESTRUM CVX
• 240 Series Axial-Flow (5140, 6140, 7140, 7240, 8240, 9240)
• Austoft 9900
• Austoft 4010 Maxx
• Magnum (180, 200, 220, 240, 250, 280, 310, 340)
• Puma (150, 165, CVT models)
• Farmall (40, 45, 50 with Cab/CVT)
• Patriot (2250, 3240, 3340, 4440)
• Titan (3040, 3540, 4040, 4540)

1. 1

   Perform a system purge: Turn off the engine and wait at least 2 minutes for the SCR system to empty DEF from the lines before disconnecting the battery.

2. 2

   Inspect the upstream NOx sensor's 5-pin electrical connector (C186) and the wiring harness leading to the ECU for melted wires, chafing, or corrosion that could cause a short circuit.

3. 3

   Verify that the sensor is receiving the correct supply voltage (12V or 24V depending on the machine) and that the CAN bus communication lines are intact.

4. 4

   Clear the OBD fault codes using a diagnostic tool. If code 19059 immediately returns upon key-on or engine start, the internal short circuit is hard-faulted and the sensor must be replaced.

1. 1

   Preparation

   Ensure the machine is parked safely, the engine is cool, and the battery is disconnected (after the 2-minute SCR purge cycle).

2. 2

   Locate the Sensor

   Locate the upstream NOx sensor on the exhaust pipe, positioned before the DOC/SCR catalyst assembly.

3. 3

   Removal

   Disconnect the sensor's electrical connector. Carefully unscrew the NOx sensor from the exhaust pipe. Note: Do not use an impact wrench to remove or install the sensor, as this can damage the exhaust bung threads.

4. 4

   Cleaning

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

5. 5

   Installation

   Thread the new upstream NOx sensor into the exhaust pipe. Warning: Do not touch the ceramic probe of the new sensor with bare fingers, as oil contamination will cause premature failure. Tighten to the OEM torque specification.

6. 6

   Reconnection

   Route the sensor wiring away from extreme heat sources and reconnect the 5-pin harness.

7. 7

   Testing

   Reconnect the battery, turn the ignition on, and use a diagnostic tool to clear the fault codes. Start the engine and perform a functional test to ensure the code does not return and the SCR system operates normally.