Case IH 19054 (F-3224-05) – Engine Control Module (ECM) / Engine ECU: Upstream NOx sensor internal failure (Open Circuit Error)

The engine's control system has detected a break or open circuit within the internal circuitry of the upstream Nitrogen Oxide (NOx) sensor or its internal heating element. Because of this open circuit, the sensor cannot accurately measure the pollutants coming directly from the engine combustion chambers before they enter the aftertreatment system.

• VESTRUM CVX
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Austoft 9900 Sugarcane Harvesters
• Farmall CVT Tractors (40, 45, 50)
• Steiger
• Magnum
• Puma

1. 1

   Verify the 'Dew Point' Warm-Up Cycle: The upstream NOx sensor has a built-in heating cycle and will read 'Not Ready' for approximately 5 minutes after startup. Wait to see if it comes online before condemning the sensor.

2. 2

   Inspect the wiring harness and the electrical connector (e.g., C186) between the upstream NOx sensor and the ECM for disconnected wires, backed-out pins, or corrosion.

3. 3

   Check the sensor's power supply and ground circuits using a multimeter to ensure the open circuit is not on the machine's harness side.

4. 4

   Verify continuity on the Engine CAN bus (CAN C) lines, as the NOx sensor communicates its data to the ECM via this network.

1. 1

   Preparation

   Turn off the engine, turn off the battery disconnect switch, and allow the exhaust system to cool completely.

2. 2

   Locate the sensor

   Locate the upstream NOx sensor. It is positioned in the exhaust pipe before the Diesel Oxidation Catalyst (DOC).

3. 3

   Disconnect

   Unplug the electrical connector linking the NOx sensor module to the engine wiring harness.

4. 4

   Removal

   Carefully unscrew the NOx sensor probe from the exhaust pipe. If the sensor is seized due to heat cycling, apply penetrating oil to the threads and allow it to soak before attempting removal.

5. 5

   Installation

   Apply a high-temperature anti-seize compound to the threads of the new upstream NOx sensor (if it does not come pre-applied). Thread it into the exhaust pipe and torque it to the manufacturer's specification.

6. 6

   Reconnection

   Securely plug in the sensor's electrical connector and ensure the wiring is routed away from extreme heat sources.

7. 7

   Verification

   Turn the battery disconnect and key switch ON. Connect your diagnostic tool and monitor the sensor's status. Wait up to 5 minutes for the sensor to complete its 'Dew Point' cycle and verify it changes to a 'Ready' state. Clear the 19054 fault code and run the engine to ensure the code does not return.