Case IH 19142 – Engine Control Module (ECM/EDC) or Dosing Control Unit (DCU): DEF/AdBlue quality sensor temperature failure

The temperature reading reported by the DEF quality sensor deviates significantly from the temperature reading reported by the DEF level sensor, indicating a plausibility failure where one of the temperature thermistors has failed or is reading inaccurately.

• Tier 4b
• 240 Series Axial-Flow Combines
• Farmall Series (40-45-50 CVT, 115U)
• Magnum
• Steiger

1. 1

   Check for related codes such as 19141 (Diesel fuel detected in DEF tank) or 19144 (CAN timeout error). If CAN communication codes are present, the issue is likely electrical rather than a sensor failure.

2. 2

   Connect the Case IH Electronic Service Tool (EST) and monitor live data parameters for both 'DEF Level Temperature' and 'DEF Quality Temperature' to note the variance.

3. 3

   Inspect the wiring harness and the connector at the DEF tank header unit for corrosion, water intrusion, or damaged pins causing high resistance.

4. 4

   Ensure the DEF tank is filled with clean, approved DEF/AdBlue, as contaminated fluid can sometimes cause erratic sensor behavior.

1. 1

   Power Down

   Turn off the machine and disconnect the battery ground to ensure safety while working on the SCR electrical system.

2. 2

   Access the DEF Tank

   Locate the DEF tank and clean the area around the top of the tank where the DEF sending unit (header) is mounted to prevent dirt from falling into the tank.

3. 3

   Disconnect Harness

   Unplug the electrical connector from the DEF quality/level sensor assembly.

4. 4

   Remove the Sensor Assembly

   Unbolt or unscrew the retaining ring holding the sending unit in the tank.

5. 5

   Extract and Replace

   Carefully pull the old sensor assembly out of the tank. Install the new OEM DEF sensor assembly, ensuring the sealing O-ring or gasket is properly seated.

6. 6

   Reassemble and Refill

   Secure the retaining ring, reconnect the electrical harness, and reconnect the battery. If the tank was drained, refill it with fresh, approved DEF.

7. 7

   Clear Codes

   Connect the diagnostic tool, clear the inactive 19142 fault code, and run the engine. Verify that the live temperature readings for both the level and quality sensors now match.