Case IH F-3223-06 - ECU – Engine Control Unit (ECU) / Engine Management System (EMS): Upstream NOx sensor internal failure (Heater Short Circuit Error)

The upstream Nitrogen Oxide (NOx) sensor contains an internal heating element required to bring the sensor up to operating temperature. This code indicates that the Engine Management System has detected a short circuit specifically within this internal heater circuit.

• MAGNUM AFS Connect
• 240 Series Axial-Flow Combines
• Austoft 9900 Sugarcane Harvesters
• Magnum (180, 200, 220, 240, 250, 280, 310, 340)
• Puma (150, 165)
• Farmall (110A, 120A, 130A, 140A)
• Steiger models
• Patriot (2250, 3240, 3340, 4440)
• Titan (3040, 3540, 4040, 4540)

1. 1

   Verify symptoms such as SCR System Malfunction warning, AdBlue/DEF warning light, and engine derate (power loss, torque limitation, or speed restriction).

2. 2

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

3. 3

   Assess the failure: internal shorts cannot be repaired, indicating the sensor unit itself must be replaced.

1. 1

   Locate the Component

   Find the upstream NOx sensor located directly before the DOC in the exhaust system.

2. 2

   Replacement

   Replace the upstream flow NOx Sensor. Remove the defective sensor and disconnect its module from the wiring harness.

3. 3

   Install New Sensor

   Install the replacement 24V NOx sensor.

4. 4

   Clear Codes

   After installation, the ECU will monitor the new sensor values. Clear the inactive fault codes from the Engine Management System to restore full engine power and exit the SCR inducement/derate mode.