2007 GMC Sierra 3500 Classic Oxygen Sensor

You must not apply contact cleaner or other materials to the sensor or vehicle harness connectors, and do not damage the sensor pigtail and harness wires in such a way that the wires inside are exposed.

The oxygen sensor may be difficult to remove when the engine temperature is below 48°C (120°F). Excessive force may damage threads in the exhaust manifold or the exhaust pipe.

You shall make a code clear with a scan tool, regardless of whether or not a DTC is set, and reset the HO2S heater resistance learned value with a scan tool, where available.

You shall remove the HO2S and visually inspect the portion of the sensor exposed to the exhaust stream to check for contamination. If contaminated, the portion of the sensor exposed to the exhaust stream will have a white powdery coating. Silicon contamination causes a high but false HO2S signal voltage. The control module will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem.

You shall not remove the pigtail from either the heated oxygen sensor (HO2S) or the oxygen sensor (O2S). Removing the pigtail or the connector will affect sensor operation.