Case IH 3528 (DTC 319E) - ECU – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Downstream NOx sensor values are not plausible

The control module is receiving a signal from the downstream Nitrogen Oxide (NOx) sensor that does not logically align with the expected emissions output based on current engine load, fuel consumption, and DEF (Diesel Exhaust Fluid) dosing rates. It points to a failure in the SCR (Selective Catalytic Reduction) system's ability to accurately monitor exhaust emissions.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• 5130
• 6130
• 7130
• 7230
• 8230
• 9230
• Magnum Series (180, 190, 210, 225, 235, 260, 290, 315, 340, 370)
• Steiger Series (350, 400, 450, 500, 550, 600)
• Quadtrac (450, 500, 550, 600)
• Titan 3030
• Titan 3530
• Titan 4030
• Titan 4530
• Titan 2240
• Titan 4430
• 521F
• 621F
• 821F
• 921F
• 1021F
• 1121F

1. 1

   Check for Accompanying Codes: Verify if there are other NOx sensor codes present. Codes like 3529 (Open Circuit), 3530 (Short Circuit), or 3533 (CAN timeout) indicate a hard electrical failure, whereas 3528 alone usually points to a failed sensor probe or heavily degraded sensor.

2. 2

   Check DEF/AdBlue System: Ensure the DEF tank is full of high-quality, unexpired fluid, as poor DEF quality can cause the downstream sensor to read implausible emissions levels.

3. 3

   Inspect the Wiring Harness: Check the wiring and connector leading to the downstream NOx sensor for melting, chafing, or corrosion, which can distort the signal sent to the ECU.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical shorts and allow the exhaust system to cool completely.

2. 2

   Locate the Sensor

   Locate the downstream NOx sensor, which is threaded into the exhaust pipe after the SCR catalyst/DEF injector.

3. 3

   Disconnect

   Unplug the electrical connector linking the NOx sensor to the machine's wiring harness.

4. 4

   Remove the Sensor

   Using an appropriate O2/NOx sensor wrench, carefully unthread the old sensor from the exhaust pipe.

5. 5

   Install the New Sensor

   Thread the new NOx sensor into the exhaust bung and tighten to the manufacturer's specified torque.

6. 6

   Reconnect

   Plug the new sensor's electrical connector into the harness.

7. 7

   Clear Codes

   Reconnect the battery. You must use an on-board computer scan tool to clear the error codes. Documentation notes that error clearing is required once after fitting the new sensor to restore normal operation and exit any engine power loss/derate modes.