Case IH 19536 – Engine Control Module (ECM) or SCR/Denoxtronic Aftertreatment Control Module: Power supply monitoring for the NOx sensor

The control module has detected an irregularity in the electrical power supply circuit feeding the Nitrogen Oxide (NOx) sensor. The voltage may be out of the expected range, or there may be an open circuit, short to ground, or short to battery voltage in the sensor's power supply line.

• Tier 4b
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Puma series (130 to 230)
• Maxxum series (110 to 140)
• Farmall series (110A to 140A)
• Combine 5140
• Combine 6140
• Combine 7140
• Combine 7240
• Combine 8240
• Combine 9240
• Patriot 2250
• Patriot 3240
• Patriot 3340
• Patriot 4440
• Titan 3040
• Titan 3540
• Titan 4040
• Titan 4540
• Farmlift Telehandlers
• N-Series Tractor Loader Backhoes
• F-Series Wheel Loaders

1. 1

   Visually inspect the NOx sensor connector for bent pins, corrosion, melted plastic, or traces of water intrusion

2. 2

   Check overall system voltage to ensure batteries are fully charged and the alternator is functioning correctly (low voltage can trigger power supply faults)

3. 3

   Perform a harness voltage test with the ignition ON (engine off) at the power supply pins on the machine-side harness. Target value should match system voltage (12V/24V, or 16V-36V for 24V systems)

4. 4

   Test continuity and resistance on the wiring harness between the NOx sensor connector and the ECM to check for open circuits or shorts to ground

1. 1

   Preparation

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical shorts. Allow the exhaust system to cool completely.

2. 2

   Locate the Sensor

   Identify whether the upstream (near the turbocharger) or downstream (after the SCR catalyst) sensor is triggering the fault.

3. 3

   Removal

   Disconnect the NOx sensor's electrical connector. Use a specialized NOx sensor socket (usually 22mm or 24mm) to remove the sensor probe from the exhaust pipe. Tip: If the sensor is seized, apply penetrating oil to the threads and allow it to soak to prevent stripping the exhaust bung.

4. 4

   Installation

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (do NOT get any on the sensor tip, as this will ruin the element). Thread the sensor in by hand, then torque to OEM specifications.

5. 5

   Routing

   Reconnect the electrical connector. Ensure the sensor's wiring is secured with zip-ties or clips, keeping it safely away from moving parts and extreme exhaust heat.

6. 6

   Reset

   Reconnect the battery. Connect a diagnostic scan tool (such as the CNH Electronic Service Tool) to clear fault code 19536. Some systems may require a specific 'NOx sensor replacement' reset routine in the ECM to calibrate the new sensor.

7. 7

   Validation

   Start the engine and allow it to reach operating temperature to verify the code does not return.