CM850 Electronic Control System – 019-451   Aftertreatment Outlet NOx Sensor

The NOx sensor is located either in the exhaust muffler or in the exhaust tailpipe.

The NOx sensor is a one-piece unit made up of two parts, a small module with a wire connection to the metal sensor body that sits in the exhaust system. The parts must not be separated.

The NOx sensor is not serviceable. If proved to be faulty, the part must be replaced.

CAUTION  Exhaust catalyst will stay hot to touch for long periods of time after the engine has been switched off.

CAUTION  The NOx sensor will stay hot to touch for long periods of time after the engine has been switched off. The NOx sensor will also be hot if the engine keyswitch is on.

CAUTION  Do not underseal or coat/paint any part of the NOx sensor.

CAUTION  Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  The catalyst substrate contains Vanadium Pentoxide. Vanadium Pentoxide has been determined by the State of California to cause cancer. Always wear protective gloves and eye protection when handling the catalyst assembly. Do not get the catalyst material in your eyes. In case of contact, immediately flood eyes with large amounts of water for a minimum of 15 minutes. Avoid prolonged contact with skin. In case of contact, immediately wash skin with soap and water.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Check for active fault codes with INSITE™.
• Disconnect the batteries. Refer to the OEM instructions.

Disconnect the push-fit connector from the NOx sensor module.

Remove the two retaining bolts.

Remove the retaining nut and pull out the NOx sensor from the exhaust catalyst/exhaust pipework.

Visually inspect the NOx sensor for damage to wiring or the body of the sensor.

CAUTION  Do not clean the NOx sensor with any kind of fluid.

CAUTION  Do not immerse the NOx sensor in water or any kind of chemical wash.

CAUTION  Do not jet-wash or steam clean the NOx sensor.

Visually inspect the tip of the NOx sensor for damage.

Apply a light coating of anti-seize compound, Part Number 3824879, to the threads of the NOx sensor.

Install the NOx sensor to the exhaust system and tighten the retaining nut.

Ensure that the NOx sensor is connected to the OEM wiring harness.

Ensure that the small module is secured to the application by the two mounting bolts.

Refer to OEM service information for location and torque.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Connect the batteries. Refer to the OEM instructions.
• Run the engine.
• Check there are no active faults codes using INSITE™.