New Holland ENG 3533 – Engine ECU (EDC): CAN Message timeout Nox (from Nox Sensor) - CAN timeout

The engine control module has lost Controller Area Network (CAN) data link communication with the Nitrogen Oxide (NOx) sensor. The sensor is failing to report its data to the network within the expected timeframe, which prevents the emissions system from verifying the efficiency of the SCR (Selective Catalytic Reduction) system.

• T6 series (T6.125 to T6.180)
• T7 series (T7.165S to T7.270)
• T8 series (T8.320 to T8.435)
• T9 series (T9.435 to T9.565)
• CR series (CR9090)
• CX series (CX8080, CX8090 Elevation)
• W190B

1. 1

   Inspect the Wiring Harness: Check the wiring harness leading to the NOx sensor for chafing, breaks, or melted insulation.

2. 2

   Check the Connector: Disconnect the NOx sensor and inspect the pins for corrosion, moisture, or pushed-out terminals.

3. 3

   Verify Power and Ground: Ensure the NOx sensor is receiving proper battery voltage and has a solid ground connection. The sensor cannot communicate on the CAN bus without power.

4. 4

   Check CAN Bus Integrity: Test the CAN High and CAN Low lines at the sensor connector for proper resistance and voltage to ensure the network itself is intact.

5. 5

   Scan for Related Codes: Look for other CAN timeout codes. If multiple modules are timing out, the issue is likely a central CAN bus wiring fault rather than the sensor itself.

1. 1

   Turn off ignition and disconnect battery

   Turn off the machine's ignition and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the faulty NOx sensor

   Locate the faulty NOx sensor on the exhaust system (typically downstream of the SCR catalyst, though some machines have both upstream and downstream sensors).

3. 3

   Disconnect electrical connector

   Disconnect the electrical connector from the NOx sensor module.

4. 4

   Unbolt sensor module

   Unbolt the sensor module from its mounting bracket.

5. 5

   Unscrew NOx sensor probe

   Carefully unscrew the NOx sensor probe from the exhaust pipe. (Use penetrating oil if the threads are seized to avoid damaging the exhaust bung).

6. 6

   Install new NOx sensor probe

   Install the new NOx sensor probe into the exhaust and tighten to the manufacturer's torque specification.

7. 7

   Mount new sensor control box

   Mount the new sensor's control box to the bracket and reconnect the electrical harness.

8. 8

   Reconnect battery

   Reconnect the battery.

9. 9

   Clear stored DTCs

   Connect a diagnostic scan tool to the machine and clear the stored DTCs. (Error clearing is required once after fitting the new NOx sensor so the ECU recognizes the new component).