Case IH 19262 (DTC 659A) - ECU – Engine Control Unit (ECU) or Aftertreatment System ECU (DCU): DEF/AdBlue tank heater actuator short circuit to battery failure

The control module has detected that the electrical circuit for the DEF tank heater actuator (specifically the coolant control valve solenoid) is shorted to a high voltage source (the battery). This prevents the valve from operating correctly, which can lead to the DEF freezing or the tank overheating if the valve is stuck open.

• MAXXUM T4E
• 240 Series Axial-Flow Combines
• Magnum Series Tractors
• Steiger Series Tractors
• Maxxum and Puma Series Tractors
• Farmlift Telescopic Handlers

1. 1

   Stop the engine and allow it to cool completely before performing checks on the pressurized cooling system

2. 2

   Inspect the wiring harness and connector pins at the DEF tank heater coolant control valve for damaged wires, chafing, loose machine grounds, debris, or water ingress

3. 3

   Use a multimeter to check the wiring between the ECU and the heater valve for a short to battery voltage

4. 4

   Test the solenoid of the DEF tank heater coolant valve itself for an internal short circuit

5. 5

   Verify that the coolant hoses are routed correctly (e.g., the DEF heater line with the 'red' band must be connected to the top tube running to the front of the engine head) to prevent continuous hot water circulation

1. 1

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes.

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the DEF tank heater coolant control valve (typically located inline on the coolant hoses routing to the DEF tank).

   Locate the DEF tank heater coolant control valve (typically located inline on the coolant hoses routing to the DEF tank).

3. 3

   Disconnect the electrical harness connector from the valve.

   Disconnect the electrical harness connector from the valve.

4. 4

   Clamp the coolant hoses on both sides of the valve or drain a sufficient amount of engine coolant to prevent fluid loss and contamination.

   Clamp the coolant hoses on both sides of the valve or drain a sufficient amount of engine coolant to prevent fluid loss and contamination.

5. 5

   Loosen the hose clamps and disconnect the coolant hoses from the faulty valve.

   Loosen the hose clamps and disconnect the coolant hoses from the faulty valve.

6. 6

   Remove the mounting hardware and the old valve.

   Remove the mounting hardware and the old valve.

7. 7

   Install the new DEF tank heater coolant control valve and secure it with the mounting hardware.

   Install the new DEF tank heater coolant control valve and secure it with the mounting hardware.

8. 8

   Reconnect the coolant hoses and tighten the hose clamps securely.

   Reconnect the coolant hoses and tighten the hose clamps securely.

9. 9

   Reconnect the electrical harness connector.

   Reconnect the electrical harness connector.

10. 10

    Unclamp the hoses, refill the engine coolant to the proper level, and bleed the cooling system of any air.

    Unclamp the hoses, refill the engine coolant to the proper level, and bleed the cooling system of any air.

11. 11

    Reconnect the battery.

    Reconnect the battery.

12. 12

    Use a compatible diagnostic scan tool (such as the Case IH EST, Jaltest, or Noregon JPRO) to clear the fault code and run a system test to verify the valve operates without throwing a short-circuit error.

    Use a compatible diagnostic scan tool (such as the Case IH EST, Jaltest, or Noregon JPRO) to clear the fault code and run a system test to verify the valve operates without throwing a short-circuit error.