ACDelco AFS-93 Oxygen Sensor Assembly

ACDelco AFS93 GM Original Equipment heated oxygen sensor assembly is a four‑wire O2 sensor designed to monitor exhaust gas oxygen content and feed data to the engine control module to optimize fuel delivery and emissions control. Sold individually as part of the GM Genuine Parts line, this sensor replaces the original GM sensor on a broad range of GM vehicles, including Chevrolet, GMC, and Cadillac models. The AFS93 designation corresponds to the GM part number 25312191 in many catalogs, reflecting its role as a heated O2 sensor in the ECM feedback loop. Used on late‑1990s to early‑2000s GM platforms, it’s a common OE replacement for models such as the 1999 Chevrolet C3500 pickup and other GM trucks and cars that require a heated, four‑wire sensor for proper operation. As an OE part, it matches factory specifications for fit, electrical connectors, and performance within the GM fuel‑management system.