A-Premium O2 Oxygen Sensor — Downstream 4-Wire Heated, 400mm Lead for Chevy GMC Buick

A-Premium O2 oxygen sensor is a direct-fit downstream heated replacement for many Chevy, GMC, Buick, Hummer and related GM-platform vehicles, restoring accurate exhaust oxygen readings and helping emissions systems operate as designed.

This A-Premium downstream oxygen sensor is built as a direct replacement for a range of GM applications and related makes. It uses a heated, 4-wire design with a 400 mm harness to match factory connector locations and electrical requirements. The part arrives boxed with a threaded mounting and a male connector so technicians and DIYers can swap it in without needing splicing or fabrication.

Which vehicles and engine types does this O2 sensor fit?

This sensor covers many downstream (post-catalytic converter) fitments across Chevrolet, GMC, Buick, Pontiac, Saturn, Saab, Hummer and Isuzu models produced primarily in the 2007–2017 range. Fitments include V4, V6 and inline engines where factory references align with the listed OEM numbers.

• Chevrolet: Captiva Sport, Colorado, Equinox, Malibu, Orlando, Trailblazer, Captiva Sport (specific years/engines)
• GMC: Acadia, Canyon, Envoy, Terrain and related models
• Buick, Pontiac, Saturn, Saab, Hummer, Isuzu: multiple compatible years and engine sizes
• OEM reference numbers: 12599204, 12604538, 12617907 and related cross-references

What electrical and mechanical specifications should I expect?

The A-Premium sensor is a heated type with four wires and a male connector, engineered to match factory electrical signals and heater circuits. The threaded mounting and 400 mm lead provide standard fitment geometry for downstream locations.

• Wire count: 4 (heated type)
• Overall lead length: 400 mm to reach OEM harness locations
• Mount: threaded for factory-style installation
• Connector: male, no splicing required when matched to OEM harness

How does this sensor affect diagnostics and emissions-related performance?

Installing a properly functioning downstream sensor helps the engine control module verify catalytic converter efficiency and can clear codes associated with degraded downstream oxygen readings when the catalytic converter is healthy. It does not change emissions hardware — it replaces a worn or failed sensor to restore accurate monitoring signals.

• Improves downstream oxygen signal reliability for catalyst monitoring
• Reduces false fault codes related to sensor failure (when converter is OK)
• Maintains compatibility with vehicle heater circuit to reach operating temperature

What should I know about installation and replacement tips?

Replacement is straightforward for anyone comfortable with basic under-vehicle or exhaust work. Use the proper oxygen-sensor socket, anti-seize only where recommended (most aftermarket sensors come pre-treated or advise against excess compound), and torque to factory specs to avoid thread damage.

• Use an appropriate O2 sensor socket or wrench for removal/installation
• Disconnect battery before unplugging electrical connector to avoid faults
• Match OEM reference numbers and downstream location (B1S2/B2S2) before purchase

Who is this for: Technicians, independent mechanics and DIY vehicle owners who need a reliable downstream oxygen sensor that matches factory electrical and mounting specifics across many GM-based platforms. This A-Premium unit is for those replacing a failed or aging heated oxygen sensor and who want a direct-fit, boxed part with known OEM cross-references and a standard 400 mm harness for correct routing and connection.