1. PTFE Filter – The filter repels water droplets while allowing air to pass. The filter ensures clean, neutral air in the air reference.
2. Crimped Weather Seal – The crimp helps maintain seal integrity despite the expansion of the metal shell caused by multiple wide temperature excursions, from freezing cold to glowing hot.
3. Ceramic Element – The ceramic element is modified zirconium oxide, which transfers oxygen ions. This ion transfer is the basis for the operation of the oxygen sensor.
4. Stainless Steel Hex Nut – High temperature stainless steel resists corrosion and leaking.
5. Rolled Threads – Rolled threads do not have the sharp edges and burrs of cut threads. The rolled threads are easy to install and give a more consistent compression of the crush washer.
6. Stable at 1000 degrees C – The high temperature stability ensures long life at elevated exhaust temperatures.
7. Plasma Sprayed Protective Coating – High temperature plasma sprayed ceramic coatings have microscopic pores that protect the electrode and control the diffusion of exhaust gas.
8. Dual Shield – The holes in these high temperature shields are offset to inhibit the access of water droplets to the heated ceramic surfaces, thus protecting the ceramic.
9. Platinum Electrode – Platinum withstands exhaust temperatures and is both catalytic and conductive, to assist in the interchange between oxygen ions and oxygen molecules.

O2 Sensor Identification Guide

An OBD Scan Tool will usually identify Oxygen Sensors by the Bank Number (B1 = Bank 1) and Sensor Number (S1 = Sensor 1). Bank 1 will always contain Cylinder 1, which is located closest to the front of the engine.

Part manufacturers often use different terms than scan tools to identify sensor positions. Regardless of the vehicle's engine orientation, the right or left bank is determined by viewing the engine from the rear (opposite the drive belts).

Common O2 Sensor Contaminants

Oxygen (O2) Sensors commonly fail due to contamination. When checking or replacing an O2 Sensor, visually inspect the sensor body to determine if it has been contaminated by a faulty part or substance upstream, and correct the fault before replacing the sensor.

ANTIFREEZE POISONING
Common Causes: Cracked or warped cylinder head Leaking cylinder head gasket Leaking intake manifold gasket Antifreeze Poisoned O2 Sensor

SILICONE POISONING
Common Causes: Use of an improper silicone gasket sealant on the engine Silicone Poisoned O2 Sensor

CARBON BUILDUP
Common Causes: Clogged air filter Leaking or defective fuel injector Carbon Buildup O2 Sensor