Case IH 19054 (DTC E48E) - ECU – Engine Control Unit (ECU) / Engine Management System (EMS): Upstream NOx sensor internal failure (Open Circuit Error)

The system has detected an open electrical circuit within the upstream Nitrogen Oxide (NOx) sensor or its internal heater circuit. 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. An open circuit means the electrical path is broken, preventing the sensor from communicating with the control module.

• MAXXUM T4E
• Case IH 240 Series Axial-Flow® Combines
• Case IH Farmall Tractors
• Case IH Steiger series
• Case IH Magnum series tractors
• Case IH Puma series tractors

1. 1

   Inspect the wiring harness leading to the upstream NOx sensor (located before the DOC) for chafing, melting, or physical breaks.

2. 2

   Disconnect the NOx sensor connector (e.g., C186) and check for corroded, pushed-back, or bent pins.

3. 3

   Verify that the sensor cable is properly supported. OEM guidelines state the cable must be fixed/supported within 100mm of the electronic control unit to prevent damage from exhaust system movement.

4. 4

   Test the supply voltage and ground circuits on the machine-side harness to ensure the open circuit is actually internal to the sensor and not a broken wire in the main engine harness.

1. 1

   Preparation

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

2. 2

   Locate the Sensor

   Locate the upstream NOx sensor in the exhaust pipe, situated before the Diesel Oxidation Catalyst (DOC).

3. 3

   Disconnect

   Unplug the electrical connector linking the NOx sensor to the ECU harness. Free the cable from any mounting clips or channels.

4. 4

   Removal

   Use a specialized NOx/O2 sensor socket to carefully unscrew the failed sensor from the exhaust pipe.

5. 5

   Installation

   Thread the new upstream NOx sensor into the exhaust bung by hand to prevent cross-threading. Tighten the sensor to the OEM specification (typically 50 ± 10 Nm).

6. 6

   Routing

   Reconnect the electrical plug. Ensure the new cable is routed away from extreme heat sources and secured at the proper mounting support locations (within 100mm of the module) to prevent vibration damage.

7. 7

   Clear Codes

   Reconnect the battery, turn the key on, and use a dealer-level diagnostic tool (like the Case IH Electronic Service Tool) to clear the E48E / 19054 fault code and reset the SCR system monitors.