Massey Ferguson U 520257 – Engine ECU: Static urea leakage test: Leakage detected

The engine's onboard diagnostic system has detected a loss of pressure or an active leak in the Selective Catalytic Reduction (SCR) Diesel Exhaust Fluid (DEF / AdBlue) dosing system during its static pressure test.

• 8600 Series (8650, 8660, 8670, 8680, 8690)
• 5700 S
• 6700 S
• 7700
• 8700 S
• IDEAL combines

1. 1

   Visually inspect the entire DEF/AdBlue circuit for white crystalline deposits, including the DEF tank, filler cap, and supply lines.

2. 2

   Inspect the DEF Dosing Module (Supply Module) for external leaks or internal pressure loss.

3. 3

   Inspect the DEF injector at the exhaust line/catalyst for leaks or severe crystallization blocking the nozzle.

4. 4

   Verify that the DEF pressure and backflow lines are not cracked, melted by exhaust heat, or suffering from loose connections.

1. 1

   Prepare machine and ensure safety

   Turn off the ignition, remove the key, and allow the exhaust and SCR system to cool completely.

2. 2

   Put on PPE

   Wear neoprene or reinforced gloves and safety goggles to protect against skin irritation during decontamination.

3. 3

   Clean the contaminated area

   Wash the area and any crystallized seals with warm water (or a 10% calcium hydroxide/alkali solution for severe decontamination) to dissolve dried urea and pinpoint the exact leak source.

4. 4

   Tighten or replace leaking components

   Torque loose fittings to OEM specifications. Replace cracked DEF lines. If the leak originates from the body of the DEF Dosing Module or the Injector, replace the failed component.

5. 5

   Reassemble system

   Install the new components or lines, ensuring all O-rings and seals are properly seated.

6. 6

   Reset system and verify repair

   Use the AGCO Tech Connect Diagnostics tool (TCD-CV) to clear the fault codes. Run a manual 'Static urea leakage test' via the software to pressurize the system and verify the repair holds.