Case IH 19054 – Engine Control Module (ECM) or Dosing Control Unit (DCU): Upstream NOx sensor internal failure (Open Circuit Error)

The system has detected an open electrical circuit associated with the upstream Nitrogen Oxide (NOx) sensor. This typically means there is a broken wire, an unplugged connector, or an internal failure/breakage within the sensor itself.

• Tier 4b
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Axial-Flow 5140
• Axial-Flow 6140
• Axial-Flow 7140
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Puma 150
• Puma 165
• Steiger 580
• Patriot 2250
• Patriot 3240
• Patriot 3340
• Patriot 4440
• Titan 3040
• Titan 3540
• Titan 4040
• Titan 4540

1. 1

   Inspect the wiring harness leading to the upstream NOx sensor for chafing, melting, or broken wires that would cause an open circuit.

2. 2

   Disconnect the 5-cavity female connector (C186) and check for loose pins, pushed-out terminals, water intrusion, or corrosion.

3. 3

   Turn the key to the ON position and verify that the sensor is receiving proper supply voltage and ground from the ECM.

4. 4

   If the wiring harness is intact and the connector is receiving power, the open circuit is internal to the NOx sensor probe or its attached control module, requiring replacement.

1. 1

   Preparation

   Park the machine on a flat, open surface, apply the parking brake, and turn off the engine. Allow the exhaust system to cool completely, as the NOx sensor is threaded directly into the high-temperature exhaust pipe.

2. 2

   Disconnection

   Locate the upstream NOx sensor (between the engine turbocharger and the SCR catalyst). Disconnect the 5-pin electrical connector from the machine's main wiring harness.

3. 3

   Removal

   Carefully unscrew the NOx sensor probe from the exhaust pipe. (Note: Penetrating oil may be required if the sensor threads are seized from heat cycles).

4. 4

   Installation

   Thread the new upstream NOx sensor into the exhaust pipe and tighten it to the manufacturer's specified torque.

5. 5

   Reconnection

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

6. 6

   Clear Codes

   Turn the ignition on and use a diagnostic service tool to clear the 19054 fault code from the ECM.

7. 7

   Validation

   Start the engine and allow it to reach operating temperature to verify that the SCR system is functioning properly and the code does not return.