Case IH 19077 (F-4334-10) – Engine Control Unit (ECU) or DEF/AdBlue Dosing Control Unit (DCU): DEF/AdBlue pressure stabilization failure

The Selective Catalytic Reduction (SCR) system is unable to build, stabilize, or maintain the required pressure of Diesel Exhaust Fluid (DEF) in the dosing system lines. The FMI 10 designation specifically points to an 'Abnormal rate of change' in the pressure readings. When this occurs, the system cannot properly inject DEF into the exhaust stream, which typically results in an engine power derate.

• VESTRUM CVX
• 240 Series Combines (7240, 8240, 9240)
• 150/160/250/260 Series Combines
• Magnum Tractors (180 through 380)
• Steiger Tractors (370 through 620)
• Puma Tractors (140 through 240)
• Maxxum Tractors (115 through 150)
• Optum Tractors
• Farmall Tractors (90C, 95A, 115U, 120A, 130A, 140A)
• Patriot Sprayers (2250, 3240, 3340, 4440)
• Trident 5550 Sprayers

1. 1

   Check the DEF tank for adequate fluid level and fluid quality. Ensure there is no water contamination, dirt, or heavy crystallization.

2. 2

   Inspect all DEF supply, return, and backflow lines for leaks, kinks, or blockages caused by crystallized urea.

3. 3

   Inspect the SCR dosing valve (injector) for crystallization buildup that could be causing back-pressure or preventing flow.

4. 4

   Check the wiring harness and electrical connectors at the DEF pump module for corrosion, damage, or loose connections (electrical communication stability is a known cause).

5. 5

   Look for related companion codes that might pinpoint the exact failure point, such as 19156 (DEF pump motor severe speed deviation), 19079 (DEF over pressure), or 19080 (DEF under pressure).

1. 1

   Power Down

   Turn off the machine and wait for the SCR system to complete its automatic purge cycle (usually takes a few minutes). Disconnect the battery.

2. 2

   Clean the Area

   Locate the DEF supply module (pump) near the DEF tank. Thoroughly clean the exterior of the pump and surrounding area to prevent dirt from entering the sensitive DEF lines.

3. 3

   Disconnect Electricals

   Unplug the wire harness connected to the DEF/AdBlue Control Module and pump motor.

4. 4

   Disconnect Lines

   Carefully disconnect the DEF supply and return lines. Cap the lines immediately to prevent fluid contamination and crystallization.

5. 5

   Remove the Pump

   Remove the mounting hardware securing the DEF pump module to the chassis/bracket and remove the faulty unit.

6. 6

   Install New Pump

   Mount the replacement DEF pump module and secure it with the mounting hardware.

7. 7

   Reconnect

   Remove the caps and reconnect the DEF lines (listen for the click to ensure they are seated). Reconnect the electrical harness.

8. 8

   Test and Clear

   Reconnect the battery. Use a dealer diagnostic tool to clear the 19077 fault code. Run a DEF system prime/leak test via the diagnostic software to ensure the new pump builds and stabilizes pressure correctly.