Case IH 17752 (F-519056-07) - ECU – Engine Control Unit (ECU): DEF/AdBlue dosing valve is stuck closed at low voltage.

The system has detected that the DEF (Diesel Exhaust Fluid) dosing valve (also known as the DEF injector) is mechanically stuck in the closed position or failing to open when commanded under low voltage conditions. This prevents the proper amount of DEF from being injected into the exhaust stream, which will eventually lead to a derate condition due to high NOx emissions.

• VESTRUM CVX
• Magnum (180-380)
• Steiger (350-600)
• Puma (140-240)
• Maxxum (115-150)
• Optum (270-300)
• Farmall (40-50 CVT models)
• Patriot series
• Axial-Flow series

1. 1

   Check the DEF pump/dosing valve dedicated fuse and inspect the wiring harness and connector at the dosing valve for corrosion, broken pins, or chafed wires that could cause a low voltage drop.

2. 2

   Remove the DEF dosing valve from the exhaust pipe and inspect the nozzle for crystallized DEF, which is a common cause of a mechanically stuck-closed valve.

3. 3

   Check the DEF tank for contaminated or degraded reducing agent. Drain and flush if contamination is found.

4. 4

   Check the DEF supply module main filter, as a clogged filter can restrict pressure and mimic a stuck valve.

5. 5

   If available, swap the DEF supply module/valve with a known working unit to verify if the module itself is defective before purchasing a replacement.

1. 1

   Preparation

   Turn off the machine and allow the SCR system to complete its purge cycle (wait at least 2 minutes after key-off). Disconnect the battery.

2. 2

   Removal

   Disconnect the electrical connector and the DEF supply line from the dosing valve. Remove the mounting bolts securing the dosing valve to the exhaust SCR mixing pipe.

3. 3

   Cleaning (If Applicable)

   If the nozzle is heavily crystallized but the solenoid is intact, carefully clean the nozzle using warm distilled water (do not use harsh chemicals or tap water, which can poison the SCR catalyst).

4. 4

   Replacement

   If the valve is mechanically failed or the solenoid is burnt out, install a new DEF dosing valve. Torque the mounting bolts to OEM specifications.

5. 5

   Filter Maintenance

   Replace the DEF supply module main filter, as this should be done whenever the dosing system is serviced.

6. 6

   Reassembly & Testing

   Reconnect the DEF lines and electrical harness. Reconnect the battery.

7. 7

   Calibration/Clearing

   Use the Case IH Electronic Service Tool (EST) to clear the logged 17752 fault code. Run a dynamic DEF leak/dosing test or operate the engine at a high speed/load point to verify the valve cycles properly and the code does not return.