Case IH 19105 – Engine Control Module (ECM) or DEF Dosing Control Unit (DCU): DEF/AdBlue tank heater ECU driver over temperature failure

The engine or emissions control module has detected an over-temperature condition on the driver circuit that controls the DEF/AdBlue tank heater actuator (Coolant Control Valve). This usually means the Coolant Control Valve (CCV) is stuck open or malfunctioning, allowing hot engine coolant to continuously circulate through the DEF tank heating loop and overheat the DEF tank.

• Tier 4b
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Steiger
• Magnum
• Puma
• Maxxum

1. 1

   Check the Coolant Control Valve (CCV) by feeling the coolant lines running to the DEF tank level unit; if they are excessively hot when the system should not be calling for heat, the valve is likely stuck open.

2. 2

   Verify DEF tank coolant hose routing (especially on Fargo plant tractors). The DEF heater line with the 'red' band must be connected to the top tube running to the front part of the engine head.

3. 3

   Inspect the wiring harness and connectors at the DEF heater control valve for shorts, corrosion, or damage that could cause the ECU driver to draw excessive current.

1. 1

   Correct Hose Routing

   If the coolant hoses were installed incorrectly, swap them to their correct orientation. Note: If the hoses were connected wrong for an extended period, the valve may have sustained internal damage and will still need to be replaced.

2. 2

   Replace the Heater Control Valve

   If the valve is sticking intermittently or stuck open (and hose routing is correct), the valve assembly must be replaced.

3. 3

   Clear the Code and Reboot

   Once the mechanical repair is complete, use a diagnostic tool to erase the fault code.

4. 4

   Power Cycle

   Turn the machine completely off and back on (reboot the tractor like a computer) to reset the modules and verify the code does not return during operation.