A-Premium 2-Pack Upstream and Downstream O2 Oxygen Sensor

Overview

Not a single sensor, this pack holds two O2 sensors, one for the position before the catalytic converter and one after it. Each threads into the exhaust and sends an analog signal that tells the engine computer how rich or lean the exhaust is.

Buying the pair together means both sensors are fresh, which helps when one fault code has already pointed at the exhaust. What is missing is fitment: the listing gives a part number but no make, model or year, and the guarantee covers the item only.

Who it's for

Owners and mechanics fixing a check engine light tied to the oxygen sensors who can verify the number on their originals. Without a vehicle list, shopping by make alone is a gamble.

Pros and cons

Performance notes

The sensor reads exhaust oxygen content and sends a voltage the engine computer uses to adjust fuel. The upstream sensor drives that adjustment, while the downstream one checks the converter, so each must match its position and connector.

Specifications