Case IH F-5715-09 - ECU – ECU: CAN timeout error from downstream NOx sensor

The control module has lost communication with the downstream Nitrogen Oxide (NOx) sensor over the Controller Area Network (CAN) bus. The sensor is failing to broadcast its data messages to the network within the expected time threshold.

• MAGNUM AFS Connect
• Magnum AFS Connect series
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400
• Steiger series
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Maxxum
• Puma series
• 240 Series Axial-Flow Combines
• 250 Series Axial-Flow Combines
• 7240
• 8240
• 9240
• 7250
• 8250
• 9250
• Patriot 3240
• Patriot 3340

1. 1

   Inspect the wiring harness and connector leading to the downstream NOx sensor for physical damage, melting from exhaust heat, or chafing.

2. 2

   Disconnect the sensor and check the pins for moisture, water intrusion, or corrosion.

3. 3

   Verify that the NOx sensor connector is receiving proper voltage and has a solid ground connection.

4. 4

   Test the CAN High and CAN Low lines for continuity between the sensor harness and the ECU.

5. 5

   Check if other CAN bus fault codes are present to rule out a broader CAN bus wiring fault.

1. 1

   Turn off the machine, remove the key, and disconnect the battery

   to ensure safety and prevent electrical shorts.

2. 2

   Locate the downstream NOx sensor.

   It is mounted directly on the exhaust pipe after the Selective Catalytic Reduction (SCR) catalyst and Diesel Oxidation Catalyst (DOC).

3. 3

   Disconnect the electrical connector of the downstream NOx sensor

   from the machine's main wiring harness.

4. 4

   Carefully unscrew the NOx sensor from the exhaust pipe

   using a specialized NOx sensor socket or wrench. (Penetrating oil may be required if the sensor is seized due to extreme exhaust heat).

5. 5

   Apply a high-temperature anti-seize compound to the threads of the new NOx sensor

   (if it is not already pre-applied by the manufacturer). Ensure no compound touches the sensor tip, as this will ruin the sensor.

6. 6

   Thread the new sensor into the exhaust pipe by hand

   to prevent cross-threading, then tighten it to the manufacturer's specified torque.

7. 7

   Reconnect the electrical connector to the wiring harness

   ensuring the locking tab clicks securely into place.

8. 8

   Reconnect the battery.

9. 9

   Connect a diagnostic tool to the machine and clear the F-5715-09 / 3533 fault code.

   A warm-up cycle or forced regeneration may be required to initialize the sensor, clear the 'not ready' status, and verify the repair.