Case IH 17923 (F-519694-14) - ECU – ECM: Differential pressure sensor: hoseline connection failure only.

This code indicates a physical or pneumatic issue with the hoses that connect the Diesel Particulate Filter (DPF) / Selective Catalytic Reduction (SCR) system to the differential pressure sensor. The system has detected that the pressure sensing hose line upstream or downstream from the catalyst filter is either detached, leaking, melted, or completely blocked by soot/carbon buildup, preventing the sensor from accurately reading the exhaust backpressure.

• VESTRUM CVX
• Case IH Farmall series (e.g., 105C, 115C)
• Case IH Maxxum series tractors
• Case IH Puma series tractors
• Machines utilizing the MTA CCM & APH Stage V MR architecture

1. 1

   Visually inspect the rubber/silicone hoses running from the DPF differential pressure sensor to the exhaust pipe for tears, heat damage (melting), or complete detachment.

2. 2

   Disconnect the hoses and check for heavy soot, carbon, or ice buildup blocking the lines.

3. 3

   Inspect the metal tubes/bungs on the exhaust pipe where the hoses attach, as these frequently plug up with hard carbon.

4. 4

   Verify the 3-pin electrical connector on the sensor is fully seated, free of corrosion, and receiving a 5-volt reference from the ECM.

1. 1

   Preparation

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

2. 2

   Remove hoses

   Loosen the clamps securing the differential pressure hoses to the sensor and the exhaust pipe. Remove the hoses.

3. 3

   Clear exhaust ports

   Using a pick, wire, or compressed air, clean out the metal ports on the exhaust pipe to ensure exhaust gas can flow freely into the hoses. Note: Never blow compressed air directly into the differential pressure sensor, as it will rupture the internal diaphragm.

4. 4

   Replace hoses (if damaged)

   If the hoses are brittle, cracked, or melted, replace them with high-temperature OEM emissions hoses. Ensure they are routed away from direct contact with the hottest parts of the exhaust.

5. 5

   Replace sensor (if faulty)

   If the hoses and ports are completely clear and intact, the sensor's internal diaphragm may have failed, falsely reporting a disconnected hose. Unplug the electrical harness, unbolt the sensor bracket, and install a new sensor.

6. 6

   Reassembly

   Reconnect the hoses and secure them tightly with clamps. Reconnect the electrical harness.

7. 7

   System reset

   Reconnect the battery. Use a diagnostic scan tool (like the CNH Electronic Service Tool) to clear the inactive 17923 fault code.

8. 8

   Validation

   Perform a manual/forced DPF regeneration. Monitor the DPF differential pressure live data to ensure it rises smoothly as engine RPM and exhaust flow increase.