Case IH F-3031-06 - ECU – Engine Control Unit (ECU): DEF/AdBlue tank temperature is not within acceptable limits

The DEF/AdBlue tank temperature is not within acceptable limits, meaning the Diesel Exhaust Fluid (DEF) is either overheating or freezing. This is typically caused by the coolant-based DEF heating system overheating the fluid or the temperature sensor providing an out-of-range reading.

• MAGNUM AFS Connect
• Magnum
• Steiger
• Puma
• Maxxum
• Optum
• Farmall
• 9900 series sugarcane harvesters

1. 1

   Check the DEF tank heater control valve to ensure it is not stuck open, which would allow high-temperature coolant to circulate continuously and overheat the DEF fluid.

2. 2

   Inspect the coolant hose routing to the DEF tank. Verify that the DEF heater line with the 'red' band is connected to the top tube that runs to the front part of the engine head.

3. 3

   Test the DEF temperature sensor (integrated into the DEF Head Unit) using an Electronic Service Tool (EST) to check for implausible temperature readings that indicate a failed sensor.

1. 1

   Correct Hose Routing

   If the coolant hoses to the DEF tank are reversed or installed incorrectly, reroute them to their proper orientation. Note: If the hoses were connected wrong for an extended period, the heater control valve may have been damaged and will also need to be replaced.

2. 2

   Replace the Heater Control Valve

   If the valve is stuck open and cannot be freed, or if it has failed electronically, drain a small amount of coolant, remove the faulty valve, and install a new DEF heater control valve.

3. 3

   Replace the DEF Head Unit

   If the valve and hoses are functioning normally but the temperature reading remains out of limits, the integrated temperature sensor has failed. Drop the DEF tank (if required for clearance), unscrew the DEF Head Unit/Sender assembly, and replace it with a new unit.

4. 4

   Clear Codes

   Reconnect all harnesses, refill any lost coolant or DEF, and use the Case IH Electronic Service Tool (EST) to clear the F-3031-06 fault code and verify normal operation.