Case IH 3569 – Engine Control Module (ECM / EDC): Urea quality and urea warning level 2

The Selective Catalytic Reduction (SCR) system has detected an issue with the Diesel Exhaust Fluid (DEF / Urea). The Urea Quality Sensor (UQS) has determined that the DEF concentration is outside the required specification (must be exactly 32.5% urea), or the sensor itself has failed. This Level 2 warning typically initiates an engine derate.

• Case IH Magnum Series (235 - 340 Series 4)
• Case IH Steiger Series (350 - 600 horsepower models)
• Case IH Puma Series

1. 1

   Test fluid quality: Use a DEF refractometer to test the fluid currently in the tank. It must read exactly 32.5% urea concentration. If degraded or contaminated, the fluid is the cause.

2. 2

   Visual inspection: Inspect the DEF tank for crystallization, debris, or cloudiness.

3. 3

   Harness and connector check: Inspect the Urea Quality Sensor wiring harness and the 4-terminal connector at the DEF tank header. Look for open circuits, shorts to ground, corrosion, or loose pins. Verify the power supply circuit.

4. 4

   Check for related codes: Look for accompanying codes (3565, 3573, or 3577) which can help pinpoint if the issue is a cascading failure from the Dosing Control Unit (DCU).

1. 1

   Turn off ignition

   Turn off the ignition switch.

2. 2

   Drain DEF tank

   Drain the DEF tank completely.

3. 3

   Flush tank

   Flush the tank with distilled water or fresh DEF to remove any crystallized urea or contaminants.

4. 4

   Refill tank

   Refill the tank with fresh, high-quality DEF (32.5% concentration).

5. 5

   Clear DTCs

   Use a diagnostic scan tool to clear the DTCs and reset the system.

6. 6

   Disconnect battery

   Turn off the ignition switch and disconnect the battery.

7. 7

   Locate DEF Head Unit

   Locate the DEF Head Unit on the top of the DEF tank.

8. 8

   Disconnect harness and lines

   Carefully disconnect the electrical harness connector and the DEF fluid supply/return lines from the header.

9. 9

   Remove mounting hardware

   Remove the mounting hardware securing the DEF header to the tank.

10. 10

    Extract old unit

    Extract the old DEF Head Unit assembly from the tank.

11. 11

    Install new unit

    Install the new DEF Head Unit / Quality Sensor assembly. Ensure the mounting gasket/O-ring is properly seated to prevent contamination and leaks.

12. 12

    Reconnect lines and harness

    Reconnect the fluid lines and the electrical harness.

13. 13

    Reconnect battery

    Reconnect the battery.

14. 14

    Clear codes and calibrate

    Connect a diagnostic scan tool, clear the Engine ECU and DCU fault codes, and perform a system reset/calibration.

15. 15

    Verify repair

    Run the machine to operating temperature to verify the code does not return and the engine derate is lifted.