Case IH 2772 – Engine Control Unit (ECU): Aftertreatment Outlet NOx - Data Valid but above Normal Operating Range - Least Severe Level

The Engine Control Unit (ECU) has detected that the engine's NOx emission reading is higher than the recommended environmental limits.

• VESTRUM CVX
• Puma
• Magnum
• Steiger
• Quadtrac
• Case CE equipment

1. 1

   Connect the INSITE™ electronic service tool (or Case IH EST) to read all active and pending fault codes to see if code 2773 is also present.

2. 2

   Check the quality of the Diesel Exhaust Fluid (DEF) to ensure it is not contaminated, diluted, or degraded.

3. 3

   Inspect the aftertreatment DEF injector nozzle for blockages, crystallization, or plugging.

4. 4

   Verify the voltage and operation of the Outlet NOx sensor.

1. 1

   Drain, flush, and refill DEF

   If DEF quality is poor, drain the DEF tank, flush the system, and refill with fresh, high-quality DEF.

2. 2

   Clean or replace aftertreatment nozzle

   Remove and inspect the aftertreatment nozzle. If it is plugged or blocked, clean or replace the nozzle (referencing Cummins/CNH Procedure 011-040 in Section 11 of the service manual).

3. 3

   Replace Outlet NOx Sensor

   If the DEF system is clear and the fluid is good, the root cause is likely a faulty Outlet NOx Sensor. Replace the sensor.

4. 4

   Perform NOx Reset Test

   Connect the INSITE™ electronic service tool and perform the "NOx Reset Test" to reset the On-Board Diagnostics (OBD) NOx monitor. This is a required part of the repair verification.

5. 5

   Verify repair completion

   Monitor the test screen; the status bar will display "Paused" while the monitor collects data and determines a pass/fail decision. Wait for the status bar to advance to 100% and display "Passed" to verify the repair is complete.