Case IH 19100 – DCU (Dosing Control Unit): UREA level sensor (electrical) | supply voltage error | Reductant Level Sensor - Circuit Intermittent/Erratic

The system has detected an unreliable, unstable, or intermittent circuit/supply voltage error coming from the Urea (DEF / Reductant) level sensor. This means the controller is receiving erratic voltage signals, indicating a likely electrical short, open circuit, or internal failure of the sensor itself.

• Tier 4a
• Case IH Steiger Series: 350, 400, 450, 500, 550, 600, and Rowtrac variants
• Case IH Magnum Series: 235–340 (Series 4)
• Case IH Austoft Harvesters: 9000 and 9900 series

1. 1

   Inspect the wiring harness and connectors between the DEF/Urea level sensor (located on top of the DEF tank) and the DCU for chafing, shorts to ground, shorts to power, or open circuits.

2. 2

   Disconnect the DEF header connector and check for corrosion, bent pins, moisture, or physical damage. Ensure the fit is tight when reconnected.

3. 3

   Verify the supply voltage to the sensor using a multimeter to ensure the DCU is sending the correct reference voltage.

4. 4

   Check for severe scale build-up or contamination in the DEF tank that might physically interfere with the sensor's float or ultrasonic reader.

5. 5

   Use the Electronic Service Tool (EST) to monitor the reductant level sensor readings in real-time to see if the voltage drops out intermittently when the harness is wiggled.

1. 1

   Disconnect Power

   Disconnect the machine's battery to ensure safety and prevent electrical shorts.

2. 2

   Locate the DEF Header

   Locate the DEF tank and the DEF header assembly on top of it (this unit houses the level sensor, temperature sensor, and suction/return tubes).

3. 3

   Disconnect Lines

   Carefully disconnect the electrical connector and the DEF fluid lines from the DEF header. Cap the fluid lines to prevent contamination.

4. 4

   Remove the Header

   Remove the mounting bolts or locking ring securing the DEF header to the tank.

5. 5

   Extract the Unit

   Carefully pull the DEF header assembly straight up and out of the tank. Clean the tank opening and ensure no dirt or debris falls into the DEF fluid.

6. 6

   Install New Header

   Install the new DEF header assembly, ensuring the O-ring/gasket is properly seated to prevent leaks.

7. 7

   Reconnect

   Reinstall the mounting bolts/ring, then reconnect the fluid lines and the electrical connector.

8. 8

   Restore Power

   Reconnect the battery.

9. 9

   Clear Codes

   Turn the key on and use the Electronic Service Tool (EST) to clear the fault code. Run the machine and verify the sensor reading is now stable and accurate.