Case IH 19114 (F-3031-21) - ECU – Engine Control Unit (ECU) / Engine Electronic Management (EEM): DEF/AdBlue tank temperature is not plausible - temperature too low compared to atmospheric temperature

The Engine Electronic Management (EEM) system has detected that the temperature reading coming from the DEF tank is significantly lower than the ambient atmospheric temperature. Because this condition is physically implausible, the system flags it as a sensor or circuit malfunction. This is an emissions-related fault that will eventually trigger an engine power derate (power loss) if not addressed.

• VESTRUM CVX
• Case IH 240 Series Axial-Flow Combines
• Case IH Farmall 40, 45, and 50 Tractors (with Cab and CVT Transmission)
• Case IH Vestrum Tractors
• Case IH 9900 series

1. 1

   Inspect the sensor wiring for loose contacts or physical defects (such as rodent damage or chafing).

2. 2

   Check for damaged or loose machine grounds (earths).

3. 3

   Disconnect the DEF header/sensor connector and inspect the pins for damage.

4. 4

   Check for debris or water intrusion inside the connector terminals, which is a common issue caused by pressure washing the equipment.

1. 1

   Safety First

   Stop the engine and allow it to cool completely before starting work. Do not attempt to start the engine during the service procedure.

2. 2

   Access the DEF Tank

   Locate the DEF tank and the DEF header unit (which houses the temperature sensor, level sensor, and quality sensor).

3. 3

   Wiring Repair

   If water, debris, or corrosion is found in the connector during the diagnostic checks, clean the terminals thoroughly, apply dielectric grease, and reconnect. If the wiring harness is damaged, repair or replace the affected wiring section.

4. 4

   Sensor Replacement

   If the wiring and connectors are in good condition but the code persists, the DEF tank temperature sensor is defective. Because this sensor is typically integrated into the DEF header assembly, the entire DEF header unit must be replaced.

5. 5

   Clear Codes

   Once the repair is complete, use a diagnostic tool to save the error log and then erase the fault codes from the ECU.