Case IH F-3224-09 - ECU – Engine Control Unit (ECU): CAN Message Timeout from the Upstream NOx Sensor

The control module has lost communication with the upstream NOx sensor over the CAN bus network. The module is not receiving the expected data messages from the sensor within the required timeframe.

• MAGNUM AFS Connect
• Magnum (180, 200, 220, 240, 250, 280, 310, 340, 380)
• Steiger / Quadtrac (370, 420, 470, 500, 540, 580, 620)
• Puma (150, 165, 185, 200, 220)
• Maxxum (115, 125, 135, 145, 150)
• Farmall (110A, 120A, 130A, 140A)
• Axial-Flow Combines (e.g., 240 series, 7240)

1. 1

   Inspect the wiring harness and the 5-pin electrical connector (C186) at the upstream NOx sensor for corrosion, pushed pins, melted wires, or moisture intrusion.

2. 2

   Verify that the NOx sensor is receiving proper supply voltage and has a solid ground. A lack of power will prevent the sensor's internal module from broadcasting on the CAN bus.

3. 3

   Test the CAN High and CAN Low communication lines for continuity back to the ECU. Check for shorts to ground or power, and verify the terminating resistance of the CAN network.

4. 4

   Check if other modules or sensors on the same CAN bus are also reporting timeout errors. If multiple devices are offline, the issue is likely a wiring fault or ECU issue rather than the NOx sensor itself.

1. 1

   Disconnect battery

   Turn off the engine, remove the key, and disconnect the machine's battery to prevent electrical shorts.

2. 2

   Locate sensor

   Locate the upstream NOx sensor in the exhaust system, positioned before the Diesel Oxidation Catalyst (DOC).

3. 3

   Disconnect connector

   Disconnect the sensor's electrical connector from the main wiring harness.

4. 4

   Remove faulty sensor

   Using a specialized NOx/O2 sensor socket, carefully unscrew the faulty NOx sensor from the exhaust pipe. (If it is seized, penetrating oil and heat may be required).

5. 5

   Prepare new sensor

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (if not already pre-applied by the manufacturer). Caution: Ensure no anti-seize gets on the sensor probe tip.

6. 6

   Install new sensor

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

7. 7

   Reconnect connector

   Reconnect the electrical connector, ensuring the locking tab clicks securely into place.

8. 8

   Reconnect battery

   Reconnect the battery.

9. 9

   Verify repair

   Connect a diagnostic scan tool, clear the F-3224-09 fault code, and run the engine to verify that the sensor is communicating and the code does not return.