Case IH 3476 – WPC / EDC: Coolant Pump speed: long period error (speed zero)

The system is reading a pump speed of zero for an extended period. The underlying condition is either a defective coolant pump speed sensor (sending no signal) or the coolant pump is physically standing still (seized or mechanically failed). A CAN Bus timeout error is flagged when the CAN-Receive-Frame (WPC2EDC) from the Water Pump Controller is missing.

• Magnum
• Steiger
• Maxxum
• Farmall
• combines

1. 1

   Verify if the coolant pump is actually turning or if it is physically standing still/seized

2. 2

   Test the coolant pump speed sensor to see if it has failed and is falsely reporting a zero speed while the pump is rotating

3. 3

   Inspect the CAN cable connecting the Water Pump Controller (WPC) to the EDC. Look for disconnected plugs, broken wires, or short circuits in the wiring harness

4. 4

   Check for a defective CAN controller on the Water Pump itself, which would cause the timeout error

1. 1

   Inspect the Harness

   Locate the wiring harness connecting the Water Pump Controller to the Engine ECU (EDC). Check for continuity, shorts to ground, or damaged pins. Repair or replace the wiring harness if a short circuit or break is found.

2. 2

   Evaluate the Speed Sensor

   If the wiring is intact and the pump is mechanically turning, the coolant pump speed sensor is defective. Remove and replace the speed sensor.

3. 3

   Evaluate the Coolant Pump

   If the pump is mechanically seized (standing still), drain the engine coolant, remove the drive belt/components, and replace the entire coolant pump assembly.

4. 4

   Evaluate the Controller

   If the pump rotates freely and the sensor/wiring are good, but the EDC still reports a CAN timeout (missing WPC2EDC frame), the Water Pump Controller (WPC) has failed and must be replaced.

5. 5

   Clear Codes

   After repairs, cycle the power and use a diagnostic tool to clear the fault codes and verify the pump speed registers correctly during engine operation.