Case IH 19428 – Engine Control Unit (ECU): Time to reach DEF/AdBlue closed loop control too long

The system takes an excessive amount of time to achieve closed-loop control, indicating that the system cannot build adequate DEF pressure, the exhaust is not reaching the required temperature for dosing, the DEF quality is poor, or there is a physical blockage in the dosing system.

• Tier 4b
• Steiger
• Magnum
• Farmall
• 7230
• 8230
• 580N

1. 1

   Check for Accompanying Codes: Look for supporting fault codes related to DEF pressure (e.g., 19813 or 19298 indicating urea pressure too low), NOx sensor drift, or DEF temperature out of range.

2. 2

   DEF Quantity & Doser Test: Run a DEF quantity test via the diagnostic software to ensure the doser injector is spraying the correct amount of fluid and is not clogged with crystallized urea.

3. 3

   Inspect the Coolant Control Valve (CCV): Check if the CCV is stuck open. If engine coolant flows continuously through the DEF tank heating coil, the DEF will overheat, which disrupts the dosing module's ability to cool itself and function properly.

4. 4

   Check DEF Quality: Verify that the DEF fluid has the correct 32.5% urea concentration. The DEF header assembly contains a quality sensor that monitors this; if the fluid is degraded, closed-loop control cannot be achieved.

5. 5

   Inspect Supply Lines: Check the DEF supply lines from the pump to the doser for leaks, kinks, or blockages.

1. 1

   Address Overheating

   If the DEF tank is hot to the touch or the CCV is leaking/stuck open, replace the DEF tank heater control valve. Ensure the coolant hoses are routed correctly (the line with the red band must connect to the top tube running to the front of the engine head).

2. 2

   Clean or Replace the Doser

   If the DEF quantity test fails, remove the DEF doser/injector from the exhaust. Clean any crystallized DEF using warm water. If it remains clogged or fails electronically, replace the doser.

3. 3

   Replace the DEF Header

   If the system cannot verify DEF quality or temperature accurately, the DEF header assembly (which houses the quality sensor, level float, and heating coil) must be replaced.

4. 4

   Perform an SCR Efficiency Test

   Simply clearing the fault code with a scan tool will not remove the engine derate. You must perform a successful parked regeneration followed immediately by an SCR Efficiency Test. Monitor the LARMF (Long Term Adaptation Factor) compensation; it must reach a passing threshold (typically 0.91 or higher) without interruption to successfully clear the closed-loop fault.