Case IH 19095 (DTC 2F3A) - ECU – Engine Electronic Control Module (EEM / ECM) or Dosing Control Unit (DCU): DEF/AdBlue tank temperature sensor plausibility failure.

The monitoring system has detected that the temperature value reported by the DEF (Diesel Exhaust Fluid) tank temperature sensor is implausible. This means the reading is erratic, out of the expected range, or does not logically align with other system temperatures (such as the DEF pump module temperature or ambient temperature). Because DEF freezes at 12°F and degrades in high heat, accurate temperature monitoring is critical for the DEF heater and dosing system. This is an emissions-related fault that will trigger a warning lamp and eventually induce an engine power derate (limp mode) if not corrected.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Magnum Series Tractors (235-340 Series 4, 180-380)
• Steiger 4WD Tractors
• Puma Series Tractors
• Maxxum Series Tractors
• Farmall Series Tractors
• Case IH Wheel Loaders (1121F)

1. 1

   Inspect the wiring harness and connector at the DEF tank sending unit for loose contacts, defective wiring, shorts to battery/ground, or corrosion.

2. 2

   Use a diagnostic scan tool (like CNH EST or Jaltest) to compare the DEF tank temperature reading against the ambient temperature and the DEF pump module temperature. If the machine has been sitting cold, these temperatures should be nearly identical.

3. 3

   Check the Coolant Control Valve (CCV) or tank heating valve to ensure it is not stuck open. A stuck open valve will continuously flow hot engine coolant through the DEF tank, overheating the fluid and causing a plausibility fault.

4. 4

   Check with a dealer to see if there is an ECU software update for your specific model to correct overly sensitive DEF sensor plausibility logic.

1. 1

   Preparation

   Turn off the machine and disconnect the battery. Clean the area around the top of the DEF tank to prevent dirt from falling into the tank during removal.

2. 2

   Disconnect Lines

   Carefully disconnect the electrical connector and the DEF fluid lines from the top of the DEF head unit.

3. 3

   Remove the DEF Head Unit

   Unbolt or unscrew the locking ring/flange securing the DEF head unit to the top of the DEF tank. Carefully pull the assembly straight up and out of the tank.

4. 4

   Install the New Unit

   Insert the new DEF head unit into the tank, ensuring the O-ring or sealing gasket is properly seated to prevent leaks or contamination. Secure the flange/locking ring.

5. 5

   Reconnect

   Reattach the DEF fluid lines and plug in the electrical connector.

6. 6

   Refill and Clear Codes

   Ensure the tank is filled with fresh, high-quality DEF. Reconnect the battery. Connect a diagnostic scan tool to clear the 19095 (2F3A) fault code.

7. 7

   Healing Procedure

   Run the machine's SCR "healing procedure" via the diagnostic tool to take the tractor out of derate/limp mode and verify the repair.