Case IH 19167 – Engine Control Module (ECM) or Dosing Control Unit (DCU): DEF/AdBlue quality sensor internal failure (Temperature sensor value is higher than expected)

The temperature sensing element integrated within the DEF quality sensor/sending unit is reporting a temperature value that exceeds the maximum plausible threshold, typically pointing to an internal short circuit or hardware failure within the sensor itself.

• Tier 4b
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• T7 Series Tractors
• Magnum Series Tractors
• Steiger Series Tractors
• SV340B Compact Track Loaders
• TR340 Compact Track Loaders

1. 1

   Inspect the electrical harness and connector at the DEF head unit on top of the DEF tank for corrosion, moisture intrusion, or chafed wires that could cause a short circuit.

2. 2

   Check the DEF fluid for contamination (such as diesel fuel mixed into the DEF tank, cloudiness, debris, or abnormal odors) which can cause chemical reactions that damage internal sensors.

3. 3

   Check for accompanying codes (such as 19168 for temperature lower than expected, or DEF level sensor codes) to confirm a catastrophic failure of the integrated unit.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and thoroughly clean the top of the DEF tank around the sensor mounting area to prevent dirt from falling into the tank.

2. 2

   Drain the Tank

   Drain the DEF/AdBlue fluid from the tank into a clean container. If the fluid is contaminated, dispose of it properly and flush the tank.

3. 3

   Disconnect Lines

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

4. 4

   Remove the Sensor

   Unscrew the retaining ring or remove the mounting bolts securing the DEF head unit to the tank. Carefully pull the long sensor assembly straight up and out of the tank.

5. 5

   Install the New Part

   Insert the new DEF head unit into the tank. Ensure the O-ring/gasket is properly seated to prevent leaks and contamination. Secure it with the retaining ring or bolts.

6. 6

   Reconnect

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

7. 7

   Refill

   Refill the tank with fresh, approved ISO 22241 DEF/AdBlue.

8. 8

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a diagnostic scan tool to clear fault code 19167. Run the engine to ensure the SCR system initializes without triggering a derate or power loss alarm.