Case IH F-3363-12 - ECU – EEM (Electronic Engine Management): DEF/AdBlue Tank Temperature Sensor Plausibility Failure / Stuck in Range Check

The system has detected that the temperature value reported by the DEF (Diesel Exhaust Fluid) tank temperature sensor is implausible (e.g., stuck in a specific range, drifting beyond maximum limits, or indicating insufficient heating). This can mean the sensor is measuring impossible values, the DEF tank heater valve is permanently open/defective, or the coolant lines to the tank heater are mixed up. Because this is an emissions-related fault, the engine power will eventually be reduced (derated) after a certain time limit defined by emissions authorities.

• MAGNUM AFS Connect
• Magnum series (180-380)
• Maxxum series (115-150)
• Puma series (150-240)
• Steiger 4WD series
• Farmall series (90C, 110U, etc.)
• Patriot series (e.g., 4440)
• Axial-Flow series

1. 1

   Check the wiring harness and sensor connector at the DEF tank head unit for loose contacts, corrosion, or short circuits

2. 2

   Check the DEF/AdBlue fluid quality in the tank for contamination or degradation

3. 3

   Check the coolant lines assigned to the DEF Tank Heater Valve to ensure they are correctly assembled and not reversed

4. 4

   Perform a sensor drift test using a diagnostic scan tool to monitor live DEF tank temperature data for static or drifting values

1. 1

   Save and Erase Log

   Connect your diagnostic scan tool, save the current error log, and attempt to erase the code to see if it is a hard (active) fault or a stored intermittent fault.

2. 2

   Inspect and Clean

   Disconnect the DEF head unit wiring harness. Clean the contacts with electrical contact cleaner and verify there is no moisture intrusion. Reconnect and re-test.

3. 3

   Flush Tank (If Applicable)

   If the DEF fluid is suspected to be degraded or contaminated, drain the DEF tank completely, flush it, and refill it with fresh, high-quality DEF.

4. 4

   Replace the DEF Head Unit

   If the wiring is intact, the coolant lines are routed correctly, and the fluid is clean, the temperature sensor itself is defective. On Case IH equipment, the temperature sensor is integrated into the DEF Head Unit (which also houses the level sensor and quality/concentration sensor). You must replace the entire DEF Head Unit assembly.

5. 5

   Clear Codes and Regen

   After installing the new sensor assembly, use the diagnostic tool to clear the F-3363-12 fault code. Run the engine to operating temperature and, if prompted by the software, perform a forced manual regeneration to clear any accumulated soot and reset the SCR system monitors.