Case IH 19418 – Engine Control Unit (ECU): Crankcase pressure below minimum, Open crankcase expected.

The engine's crankcase pressure sensor is reading a pressure value that has dropped below the minimum acceptable threshold. The system interprets this vacuum or lack of normal operating pressure as an "open crankcase"—meaning the engine control system suspects the crankcase is exposed to the atmosphere (e.g., a missing cap, disconnected hose) or that the sensor itself has failed and is reporting a false low reading.

• Tier 4b
• Case IH Puma
• Case IH Optum

1. 1

   Check the engine oil filler cap to ensure it is present, undamaged, and tightly sealed

2. 2

   Verify that the engine oil dipstick is fully seated in its tube and the O-ring is intact

3. 3

   Inspect the Crankcase Closed Ventilation (CCV) system for disconnected, cracked, or split breather hoses that would vent crankcase pressure to the atmosphere

4. 4

   Inspect the wiring harness and connector at the crankcase pressure sensor for chafing, corrosion, or loose pins

5. 5

   Using a diagnostic scan tool (like CNH EST), monitor the crankcase pressure sensor voltage/reading with the engine off (key on) and with the engine running to check for sensor drift or an open circuit

1. 1

   Seal the Crankcase

   If the oil filler cap or dipstick is missing or loose, reinstall or replace them.

2. 2

   Repair Breather Lines

   Reconnect or replace any damaged crankcase breather hoses. Ensure the CCV filter housing is properly sealed.

3. 3

   Test the Sensor Circuit

   If the crankcase is physically sealed, disconnect the crankcase pressure sensor. Use a multimeter to verify the sensor is receiving a 5V reference and a good ground from the Engine ECU.

4. 4

   Replace the Sensor

   If the wiring tests good but the sensor is reporting a pressure below the minimum threshold (or is stuck at a constant low value), the sensor diaphragm has likely failed. Replace the crankcase pressure sensor.

5. 5

   Clear and Verify

   Reconnect all components, clear the fault code 19418 using your diagnostic tool, and run the engine up to operating temperature to verify the code does not return.