Case IH 19817 (F-5394-07) – Engine Control Unit (ECU) or Dosing Control Unit (DCU): DEF/AdBlue dosing valve is blocked

The reagent dosing valve is blocked or stuck in the closed position. Because the valve cannot open or flow fluid, the system is unable to inject diesel exhaust fluid into the exhaust stream to reduce NOx emissions, which will eventually trigger an engine power derate.

• VESTRUM CVX
• Magnum series (180–380)
• Maxxum series (115–150)
• Puma series (140–240)
• Optum series
• Steiger series (350–600)
• Farmall models
• 240 Series Axial-Flow Combines (7240, 8240, 9240)

1. 1

   Inspect the DEF dosing injector tip and the exhaust mixing chamber for white scale deposits (crystallized DEF)

2. 2

   Verify DEF/AdBlue concentration in the tank (should measure 32.5% high-grade urea to 67.5% distilled water)

3. 3

   Inspect the exhaust pipe and mixing chamber for physical damage, cracks, or improper mounting

4. 4

   Check electrical connections and wiring harness to the dosing valve and ECU for tightness, damage, and correct pin positions

1. 1

   Access the Dosing Valve

   Locate the DEF/AdBlue dosing injector (UDV) mounted on the exhaust mixing chamber. Carefully disconnect the DEF lines and the electrical connector.

2. 2

   Remove and Inspect

   Remove the dosing injector from the exhaust pipe.

3. 3

   Clean the Components

   Look at the injector tip and inside the mixing chamber. If white scale deposits are present, clean the injector tip and the mixing chamber thoroughly. Scale prevents the vaporized DEF from mixing properly and physically blocks the valve.

4. 4

   Test the Fluid

   Measure the DEF concentration. If the concentration is incorrect or contaminated, drain the tank completely and refill with fresh, high-grade DEF/AdBlue.

5. 5

   Replace if Failed

   If there is no scale build-up on the injector tip or in the mixing chamber, and the DEF concentration is correct, the dosing injector itself has likely failed mechanically (stuck closed) and must be replaced.

6. 6

   Reassemble and Clear Codes

   Reinstall the cleaned or new dosing valve. Reconnect the lines and harness. Use an Electronic Service Tool (EST) to clear the fault code, or run the machine to verify the system is operating properly and the code goes inactive.