Case IH 3475 – Engine Control Module (ECM / ECU): CAN timeout error from coolant water pump actuator

This code indicates that the Engine Control Module (ECM) has lost Controller Area Network (CAN) communication with the electrically controlled coolant water pump actuator. The ECM is no longer receiving the expected data messages from the pump's internal module within the required timeframe.

• Steiger T4B
• 240 Series Axial-Flow Combines

1. 1

   Inspect the wiring harness and connectors between the Engine ECU and the coolant water pump actuator for chafing, corrosion, or backed-out pins.

2. 2

   Verify that the coolant water pump actuator is receiving proper battery voltage and has a solid ground connection.

3. 3

   Check the CAN High and CAN Low lines at the pump connector for continuity to the ECM and test for short circuits to ground or battery voltage.

4. 4

   With the batteries disconnected, measure the resistance across the CAN pins (a healthy CAN bus should read approximately 60 ohms).

5. 5

   Use a diagnostic tool to check for other CAN bus errors (e.g., 'Bus off failure') that might indicate a broader network issue rather than an isolated pump failure.

1. 1

   Prep the Machine

   Park the machine on a level surface, turn off the engine, and disconnect the negative battery cable.

2. 2

   Drain Coolant

   Place a clean drain pan under the engine and drain the cooling system to a level below the water pump.

3. 3

   Disconnect

   Unplug the electrical harness connector from the coolant water pump actuator.

4. 4

   Remove Components

   Remove the drive belt (if the pump is mechanically driven but electrically clutched/actuated) and remove the mounting bolts securing the water pump assembly to the engine block.

5. 5

   Clean

   Thoroughly clean the mating surface on the engine block to ensure a proper seal for the new pump.

6. 6

   Install

   Install the new electrically controlled coolant pump with a new gasket/seal. Torque the mounting bolts to the engine manufacturer's specifications.

7. 7

   Reconnect

   Reinstall the drive belt (if applicable) and plug in the electrical connector.

8. 8

   Refill and Bleed

   Refill the engine with the specified coolant. Bleed the cooling system of any trapped air according to the OEM service manual.

9. 9

   Clear Codes

   Reconnect the battery, use a diagnostic tool to clear the permanent/pending 3475 fault code, and run the engine to verify communication is restored and there are no coolant leaks.