New Holland ENG 3529 – Engine ECU: NOx Sensor Failure - Open Load

The engine control module has detected an "open load" (an open circuit or lack of electrical continuity) in the Nitrogen Oxide (NOx) sensor circuit. The system is receiving a smaller voltage than expected or no signal at all from the NOx sensor signal wire, meaning the sensor is either disconnected, the wiring is broken, or the sensor has failed internally.

• 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)
• CX series harvesters

1. 1

   Visually inspect the NOx sensor probe for an unwanted build-up of soot and exhaust debris

2. 2

   Inspect the NOx sensor signal wire and harness for broken, chafed, or shorted wires that would cause an open circuit

3. 3

   Disconnect the NOx sensor connector and the corresponding Engine Controller connector to inspect the pins for corrosion, pushed-out pins, or moisture

4. 4

   Verify that the sensor is receiving proper voltage and that the CAN data link circuit is intact

1. 1

   Power Down

   Turn off the machine and disconnect the battery to ensure safety while working on the electrical and exhaust systems.

2. 2

   Locate the Sensor

   Locate the faulty NOx sensor on the exhaust aftertreatment system (typically threaded into the exhaust pipe near the SCR catalyst).

3. 3

   Remove the Sensor

   Unplug the sensor's electrical connector. Carefully unscrew the NOx sensor from the exhaust pipe. (Penetrating oil may be required if the sensor is seized from exhaust heat).

4. 4

   Install the New Sensor

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

5. 5

   Reconnect

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

6. 6

   Clear Codes

   Reconnect the battery and turn the ignition on. Use an on-board computer scan tool or dealer diagnostic software to clear the ENG 3529 fault code. Error clearing is required once after fitting the new sensor to reset the system.