Case IH 19822 – DCU (Dosing Control Unit): UDV valve stuck position unknown error

The Urea Dosing Valve (UDV) / DEF Injector is mechanically stuck in an unknown position, causing the system's dynamic urea leakage test to detect a pressure loss or fluid leak in the SCR / DeNOX emissions system (sub-code P202D).

• Tier 4a
• Magnum Series (e.g., 235 - 340 Series 4)
• Puma Series (e.g., 125, 170, 210, 215)
• Steiger Series (e.g., 350 - 600, 470)
• Patriot Sprayers (e.g., 4430)
• Axial-Flow Combines (e.g., 7230)

1. 1

   Inspect the DEF/Urea lines, pump, and the UDV itself for physical leaks or heavy white crystallization (dried DEF fluid)

2. 2

   Inspect the wiring harness and electrical connector to the Urea Dosing Valve for shorts, open circuits, or corrosion that could be causing the valve to lose communication regarding its position

3. 3

   Disconnect the tractor's battery for a short period to see if the electronic control systems reset

4. 4

   Use the CNH Electronic Service Tool (EST) to read the DCU fault codes, verify the P202D dynamic leak test failure, and ensure no other DeNOX system codes (like pump delivery failures) are present

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical shorts and to depressurize the DEF system.

2. 2

   Locate the UDV

   Locate the Urea Dosing Valve (DEF Injector) mounted on the exhaust/SCR system.

3. 3

   Clean the Area

   Clean any crystallized DEF fluid or debris from around the valve and line connections to prevent contamination during removal.

4. 4

   Remove the Faulty Valve

   Disconnect the electrical connector and the DEF supply line from the UDV. Remove the mounting hardware and extract the stuck valve.

5. 5

   Install the New Valve

   Seat the new or remanufactured Urea Dosing Valve into the exhaust module. Secure the mounting hardware.

6. 6

   Reconnect

   Reattach the DEF supply line and plug in the electrical connector. Reconnect the machine's battery.

7. 7

   Clear Codes

   Use a CNH EST diagnostic tool (or seek assistance from a certified Case IH mechanic) to clear the 19822 / P202D codes from the Dosing Control Unit.