Case IH 19896 – Engine Control Unit (ECU): Water pump inlet pressure sensor voltage is lower than expected.

The control module is receiving a voltage signal from the water pump inlet pressure sensor that falls below the normal operating range. This condition typically points to an electrical issue such as a short to ground, an open circuit in the sensor wiring, or an internal failure of the sensor itself.

• Tier 4b
• 240 Series AXIAL-FLOW® Combines

1. 1

   Inspect the wiring harness leading to the water pump inlet pressure sensor for chafing, melting, or physical damage. Check the connector for corrosion, pushed-back pins, or moisture intrusion.

2. 2

   Disconnect the sensor and use a multimeter to verify that the sensor is receiving the correct reference voltage (typically 5V) and has a solid ground from the ECU.

3. 3

   Test the signal wire between the sensor connector and the ECU for continuity (to rule out an open circuit) and check for a short to ground, which would directly cause the low voltage condition.

4. 4

   If the wiring harness, reference voltage, and ground are all in good condition, verify if the sensor itself has failed internally.

1. 1

   Preparation

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

2. 2

   Locate the Sensor

   Locate the water pump inlet pressure sensor on the engine's cooling system circuit (near the water pump housing).

3. 3

   Disconnect

   Unplug the electrical connector from the sensor.

4. 4

   Harness Repair (If Applicable)

   If your diagnostic checks revealed a short to ground or broken wire, repair the wiring harness or replace the damaged pigtail connector.

5. 5

   Remove the Sensor

   Place a catch pan underneath the work area to catch any escaping coolant. Unscrew the faulty pressure sensor from its port.

6. 6

   Install the New Sensor

   Thread the new sensor into the port. Tighten it to the OEM torque specification (do not overtighten, as this can damage the brass/plastic threads).

7. 7

   Reconnect

   Plug the electrical connector back into the sensor, ensuring it clicks and locks into place.

8. 8

   Test

   Reconnect the battery. Start the engine and inspect the sensor area for any coolant leaks.

9. 9

   Clear Codes

   Use a diagnostic scan tool to clear the inactive 19896 fault code from the ECU and verify that it does not return during engine operation.