Case IH 19116 – Engine Control Unit (ECU) or Dosing Control Unit (DCU) / Vehicle Control Module (VCM): DEF/AdBlue tank level is too high

The DEF (Diesel Exhaust Fluid) level sensor is reporting a fluid level that exceeds the maximum expected threshold. This can be caused by a genuinely overfilled tank (filled up into the filler neck) or a malfunctioning DEF level sensor/sending unit.

• Tier 4b
• Magnum
• Puma
• Optum
• Steiger
• Quadtrac
• Farmall
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Patriot
• N-Series Tractor Loader Backhoes
• compact track loaders

1. 1

   Perform a visual fluid level check to see if the tank was recently topped off and fluid is sitting in the filler neck (genuine overfill).

2. 2

   Inspect the electrical harness and connector at the DEF sending unit for corrosion, moisture, damaged pins, or a short-to-voltage.

3. 3

   Connect a scan tool to monitor live data for the DEF level parameter to see if the sensor reads out-of-range high when the tank is not full.

4. 4

   Check if the float on the DEF level sensor is physically stuck in the 'up' position due to crystallized DEF fluid.

1. 1

   Drain excess DEF

   If the tank is simply overfilled, drain the excess DEF until it is at or below the maximum fill line, clear the code, and retest. If the sensor is faulty, proceed with replacement.

2. 2

   Preparation

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical shorts.

3. 3

   Clean the Area

   Locate the DEF sending unit (head unit) on top of the DEF tank. Thoroughly clean the area around the unit to prevent dirt, debris, or crystallized DEF from falling into the tank (the SCR system is highly sensitive to contamination).

4. 4

   Disconnect Lines

   Disconnect the electrical harness connector. Disconnect the DEF suction and return lines. If the unit is heated, disconnect the engine coolant lines routed to the header. (Have a catch pan ready for minor coolant/DEF spills).

5. 5

   Remove the Sensor

   Remove the mounting bolts or unscrew the locking ring securing the DEF head unit to the tank. Carefully pull the sending unit straight up and out of the tank.

6. 6

   Install the New Sensor

   Insert the new DEF head unit into the tank, ensuring the new O-ring/gasket is properly seated. Secure it with the mounting hardware or locking ring.

7. 7

   Reconnect

   Reattach the coolant lines, DEF fluid lines, and the electrical connector.

8. 8

   Clear Codes and Test

   Reconnect the battery and turn the ignition on. Use your diagnostic tool to clear fault code 19116. Verify that the DEF level gauge on the dash or scan tool is now reading accurately. Run the engine to ensure there are no leaks from the fluid or coolant lines.