All cars that were manufactured post-1980 feature an oxygen sensor. It is located within the emissions control system. When functioning, the O2 sensor sends data to the management computer located within the engine. In your car, a functioning O2 sensor ensures that your engine is running at top performance. Additionally, this sensor keeps your emissions in check and alerts you to when emissions are too excessive. For states that have vehicle inspection programs to regulate emissions, the use of the CEL and O2 light will alert officials to any excessive emissions. Specifications Wires:4 Package Included:4*oxygen sensor(Upstream/Downstream) Note:Please make sure that the part number and the item picture fit for your car before purchase. Fitment: Fit VIN Z; Manual Trans; Exc. Calif: 2001-2002 Dodge Ram 3500 Base 5.9L 2001-2002 Dodge Ram 3500 Custom Standard Cab Pickup 2-Door 5.9L Fit Manual Trans Exc. Calif: 2001 Dodge Ram 1500 Laramie 5.9L 2001-2002 Dodge Ram 1500 SLT 5.9L 2001 Dodge Ram 1500 Sport 5.9L 2001-2002 Dodge Ram 1500 ST 5.9L 2001-2002 Dodge Ram 2500 Base 5.9L 2001 Dodge Ram 2500 SLT Standard Cab Pickup 2-Door 5.9L Fit Manual Transmission only: 2001 Dodge Ram 1500 Laramie/SLT/Sport/ST 5.2L Product Features Improve Fuel Efficiency Improve fuel efficiency, save fuel costs, and reduce emissions of pollutants and harmful gases. Stronger Performance The light-off time is extremely short and the reaction is fast. Optimize Engine The core chip is designed and produced independently to optimize engine performance. Long Lifetime Product life is longer than normal sensors. How to Distinguish the Oxygen Sensor Poisoning? Silicon Poisoning Features: The color of the protective tube deposit is between bright white and granular light gray. Oil Pollution Features: A layer of white or gray-black oily deposit on the surface of the protective tube. Antifreeze Pollution Features: The antifreeze is leaked from the cylinder head to the engine and then burned. Lead Poisoning Features: A rusty layer on the surface of the protective tube.