New Holland 3573 – ECM: Urea Quality and Urea Level Warnings

The engine's aftertreatment system has detected a critical issue with the quality of the Diesel Exhaust Fluid (DEF). The urea concentration is outside the acceptable range of approximately 32.5%. This is a Level 3 warning, representing the most severe alert for this condition, following lower-level warnings for urea quality (codes 3565 for level 1 and 3569 for level 2). This triggers a significant engine power derate (Tortoise Mode) to limit emissions and prevent damage to the Selective Catalytic Reduction (SCR) system.

• T6 Series
• T6.125
• T6.180
• T7 Series
• T7.165
• T7.210
• T7.270
• T8 Series
• T8.275
• T9 Series
• CR Series Combine
• CX Series Combine
• FR Series Forage Harvester
• Patriot Series Sprayer
• Farmall Series
• Maxxum Series

1. 1

   Verify DEF quality using a refractometer (concentration should be approximately 32.5%).

2. 2

   Inspect the DEF tank and fluid to ensure it is adequately filled, not frozen, and free of dirt, debris, or crystallization.

3. 3

   Check for other active or stored fault codes related to the SCR system (e.g., NOx sensors, DEF dosing pump) that could indicate a related issue.

4. 4

   Inspect the wiring harness and connectors between the urea quality/level sensor and the ECM for damage, corrosion, loose pins, or water ingress.

5. 5

   Check battery voltage (should be above 12.1V) and ensure all main chassis ground connections are clean and tight to prevent erratic sensor readings.

1. 1

   Address DEF quality

   Complete all the diagnostic checks listed above. If the initial checks reveal poor DEF quality, drain the tank, flush it with deionized water, and refill with fresh, high-quality DEF from a sealed container.

2. 2

   Clear fault codes

   Use a compatible diagnostic tool, such as the New Holland Electronic Service Tool (EST), to clear all fault codes.

3. 3

   Run first engine cycle

   Start the engine and let it run at a high idle (1000 RPM or higher) for at least two minutes.

4. 4

   Perform key cycle

   Turn the engine off and leave the key in the off position for at least 15 seconds.

5. 5

   Run second engine cycle

   Restart the engine and run it at a high idle for another two minutes.

6. 6

   Re-check for faults

   Read the fault codes again. If fault code 3573 (or a related UQLS fault) returns as active, it strongly suggests a failure of the urea quality/level sensor itself.

7. 7

   Replace urea quality sensor

   If deemed faulty, disconnect the wiring, unbolt the sensor from the top of the DEF tank, and install the new unit.

8. 8

   Verify repair

   After replacing the sensor, repeat the code-clearing and engine cycle procedure to verify that the repair has resolved the issue.