Case IH 19051 (DTC E46E) - ECU – Engine Control Unit (ECU): Upstream NOx sensor internal failure (Heater Open Circuit Error)

Nitrogen Oxide (NOx) sensors contain an internal heating element designed to bring the sensor probe up to its optimal operating temperature quickly. An "open circuit" error indicates that the electrical path for this heater has been broken—most commonly due to a burned-out heating element inside the sensor itself, or a severed wire between the sensor module and the probe. Because the heater is integrated into the sensor, it cannot be serviced separately.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Steiger / Quadtrac (370, 420, 470, 500, 540, 580, 620)
• Magnum (180 through 380)
• Puma (150 through 220)
• Maxxum (115 through 150)
• Farmall series

1. 1

   Locate the upstream NOx sensor in the exhaust stream directly before the Diesel Oxidation Catalyst (DOC).

2. 2

   Inspect the wiring harness leading to the upstream NOx sensor module and the connector (C186) for melted wires, chafing, or physical damage.

3. 3

   Disconnect the sensor and check the pins for corrosion, moisture, or pushed-back terminals.

4. 4

   Verify that the sensor module is receiving proper power and ground from the ECU.

5. 5

   If the machine's harness provides proper voltage and ground to the connector and the wiring is intact, the open circuit is internal to the sensor, and the sensor assembly must be replaced.

1. 1

   Preparation

   Turn off the engine, disconnect the battery, and allow the exhaust system to cool completely to avoid severe burns.

2. 2

   Disconnect Electrics

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

3. 3

   Remove the Sensor

   Using a specialized NOx/O2 sensor socket or a suitable wrench, carefully unscrew the sensor probe from the exhaust pipe. Note: If the sensor is seized, apply penetrating oil to the threads and allow it to soak before applying force to prevent stripping the exhaust bung threads.

4. 4

   Prep the New Sensor

   If the new sensor does not have anti-seize compound pre-applied to the threads, apply a small amount. Crucial: Do not allow any anti-seize or grease to touch the sensor tip, as this will permanently contaminate and ruin the new sensor.

5. 5

   Installation

   Thread the new upstream NOx sensor into the exhaust pipe by hand to prevent cross-threading, then tighten to the OEM specified torque.

6. 6

   Routing

   Mount the sensor's control module and route the wiring exactly as it was from the factory, ensuring it is secured away from extreme heat sources and moving parts. Reconnect the electrical plug.

7. 7

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use the Case IH Electronic Service Tool (EST) or a compatible heavy-duty scan tool to clear the 19051 / E46E fault code. Start the engine and verify that the code does not return.