Case IH 19894 – Engine Control Module (ECM): Water pump inlet pressure is too low

The pressure of the engine coolant entering the water pump has dropped below the minimum acceptable threshold. This condition can lead to coolant cavitation, reduced flow, and severe engine overheating if not addressed.

• Tier 4b
• Case IH and New Holland Tier 4B (DEF/Urea) agricultural equipment
• Case IH 240 Series Axial-Flow Combines
• Case IH Puma Series Tractors

1. 1

   Check coolant level in the expansion tank and radiator

2. 2

   Inspect for external coolant leaks around the water pump weep hole, radiator, and lower coolant hoses

3. 3

   Inspect the wiring harness and connector for the water pump inlet pressure sensor for chafed wires, corrosion, or loose pins

4. 4

   Ensure the lower radiator hose is not collapsing under suction and check for blockages in the radiator core

5. 5

   Tee a mechanical pressure gauge into the water pump inlet to verify if the pressure is actually low or if the electronic sensor has failed

1. 1

   Safety First

   Shut down the machine and allow the engine to cool completely. Never open a hot, pressurized cooling system.

2. 2

   Top Off and Bleed

   If the coolant is low, fill the system with the OEM-specified coolant. Run the engine and bleed any trapped air from the cooling system, as air pockets can cause pressure drops. Clear the fault code and test run.

3. 3

   Sensor Replacement

   If the coolant level is full and a mechanical gauge shows normal pressure, the water pump inlet pressure sensor is faulty. Disconnect the electrical harness, unthread the old sensor, install the new sensor, and reconnect the harness.

4. 4

   Water Pump Inspection/Replacement

   If the mechanical gauge confirms that inlet pressure is genuinely low despite a full system, inspect the water pump drive belt for slipping. If the belt is tight, the water pump impeller may be damaged or slipping on its shaft, requiring a complete water pump replacement.

5. 5

   Final Verification

   After replacing the sensor or pump, refill the coolant, clear the ECM fault codes, and run the machine under load to ensure code 19894 does not return.