New Holland 3533 – ECM: CAN Message Timeout for NOx Sensor

The Engine Control Module (ECM) has not received the expected communication signal from the NOx sensor over the CAN bus within the allowed timeframe. This communication breakdown prevents the after-treatment system from correctly monitoring and managing exhaust emissions, which can cause the engine to enter a derated or limp mode state to prevent damage and ensure emissions compliance.

• T5.100
• T6
• T7.175
• T7.190
• T7.210
• T8.320
• T8.350
• T8.435
• T9 Series
• C238

1. 1

   Verify battery voltage is fully charged (above 12.5V) and all main battery and chassis ground connections are clean, tight, and free of corrosion.

2. 2

   Record and clear the fault code, then operate the machine to see if the code returns immediately to differentiate between an active and intermittent issue.

3. 3

   Visually inspect the NOx sensor, wiring harness, and connector for physical damage, corrosion, chafing, or exhaust heat damage.

4. 4

   Check for battery voltage and a solid ground (less than 1 ohm resistance) at the sensor connector.

5. 5

   Test the CAN bus network resistance (should be ~60 ohms) and signal voltages (CAN High/Low should be ~2.4V-2.6V).

1. 1

   Inspect wiring and connectors

   Thoroughly inspect the NOx sensor, its wiring harness, and the connector. Look for signs of physical damage, corrosion on the connector pins, chafing against the chassis, and heat damage from the exhaust system.

2. 2

   Verify power and ground

   Disconnect the sensor connector. With the key on, use a multimeter to verify the sensor is receiving battery voltage on the appropriate pins. Measure resistance between the ground pin and a known good chassis ground (must be less than 1 ohm).

3. 3

   Test CAN bus network

   With key off, measure resistance across the two CAN bus wires at the sensor connector (expected: ~60 ohms; 120 ohms indicates a missing terminating resistor or wire break). With key on, verify CAN High and CAN Low voltages are approximately 2.4V to 2.6V.

4. 4

   Clean NOx sensor

   If heavy soot or carbon buildup is found on the sensor probe, attempt cleaning the sensor tip with a specialized cleaner to see if communication restores.

5. 5

   Replace NOx sensor

   If wiring, power, ground, and CAN bus checks are good, replace the NOx sensor module as the internal electronics have likely failed.

6. 6

   Perform ECU parameter reset

   After replacing the sensor, use the New Holland Electronic Service Tool (EST) to perform an ECU parameter reset or recalibration so the system recognizes the new sensor.