Case IH 19575 – Engine Control Module (ECM) or Dosing Control Unit (DCU) / Vehicle Control Module (VCM): Short circuit error for the NOx signal

This fault code indicates that the control module has detected a short circuit in the Nitrogen Oxide (NOx) sensor circuit. This is typically caused by damaged wiring, a melted harness, or an internal short circuit within the NOx sensor probe or its integrated control module.

• Tier 4b
• Magnum (180-370)
• Steiger (350-600)
• Puma (130-230)
• Maxxum (110-140)
• Quadtrac
• Farmlift series
• N-Series Loader Backhoes (580N)
• Wheel Loaders (521F - 921F)

1. 1

   Inspect the NOx sensor wiring harness (usually a 5-pin MCON connector) for chafing, melting from exhaust heat, or pinched wires that could cause a short to ground or a short to voltage.

2. 2

   Disconnect the NOx sensor and inspect the pins for corrosion, water ingress, or bent terminals.

3. 3

   Perform a circuit isolation test: disconnect the NOx sensor and turn the key ON. If the active fault code changes from a short circuit (19575) to an open circuit code (19574 or 3529), the wiring harness is intact and the short is internal to the NOx sensor.

4. 4

   Use a diagnostic scan tool to verify exactly which sensor (upstream or downstream) is reporting the short circuit before removal.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the faulty NOx sensor on the exhaust/SCR aftertreatment pipe.

3. 3

   Disconnect

   Unplug the sensor's electrical connector from the main engine harness. Free the wire from any retaining clips.

4. 4

   Removal

   Using a specialized 22mm NOx/O2 sensor socket or a wrench, carefully unscrew the sensor from the exhaust pipe. Note: These sensors are subjected to extreme heat and often seize. Apply penetrating oil and allow it to soak if the sensor is stuck.

5. 5

   Preparation

   Check the threads on the exhaust bung and clean them with a thread chaser if necessary. Most new OEM NOx sensors come with anti-seize compound pre-applied to the threads. If yours does not, apply a small amount of sensor-safe anti-seize (avoid getting any on the sensor probe tip).

6. 6

   Installation

   Thread the new sensor in by hand to prevent cross-threading, then tighten to the manufacturer's torque specification (typically around 50 Nm / 37 lb-ft).

7. 7

   Routing

   Reconnect the electrical plug and secure the wiring harness exactly as it was from the factory, ensuring it is routed safely away from extreme exhaust heat sources.

8. 8

   Reset

   Reconnect the battery. You will likely need a dealer-level diagnostic scan tool (like CNH EST) to clear the inactive fault codes and reset the SCR system / NOx sensor learned values so the ECU recognizes the new sensor.