AdvanEX O2 Oxygen Sensor 234-4337 2-piece Set Compatible with GM Upstream/Downstream — Direct-Fit, OE-Style Replacement

AdvanEX 234-4337 is a direct-fit upstream or downstream oxygen (O2) sensor engineered to replace factory sensors on many GM-platform vehicles, restoring accurate exhaust oxygen readings for improved engine management.

This AdvanEX oxygen sensor is designed as a compatible replacement for a long list of Buick, Cadillac, Chevrolet, GMC, Isuzu, Saab, Saturn, Hammer, Oldsmobile and Pontiac models. Manufactured to meet OE-style fitment, the sensor matches common GM part numbers (including 234-4337, 234-4087 and 12578459) so you can swap it into the existing harness and mounting location without modification. It is supplied as a two-piece set for applications that require both upstream and downstream replacements.

Which vehicles will this AdvanEX O2 sensor fit?

The sensor covers a wide range of General Motors and related vehicles from the mid-1990s through early 2010s. Fitment includes multiple engine bays and both upstream (pre-catalytic converter) and downstream (post-catalytic converter) positions depending on model year and configuration.

• Buick: Allure/Lacrosse (08–09), Century (96–04), LeSabre/Park Avenue/Regal (96–03), Riviera (96–99), Rainier, Rendezvous
• Cadillac: CTS/STS/Cts-V (05–07), DeVille/Eldorado/Seville (96–99), Escalade (2007), SRX
• Chevrolet/GMC/Saturn/Isuzu: Camaro, Colorado, Equinox, Impala, Silverado, Sierra, Trailblazer, Envoy, Canyon, VUE, Ascender and more

How does this sensor compare to OEM part numbers?

AdvanEX lists cross-reference numbers to simplify verification against the original component. Compare the original part number and connector style to ensure correct selection — this reduces installation time and avoids returns.

• Cross-references include: 234-4337, 234-4087, 12578459 and 12585999
• Also listed: ES20002, 2131681 and other common GM replacement numbers
• Verify connector, thread size and wire count against your factory sensor before purchase

What should I expect during installation and operation?

Installation follows the same steps as the original sensor: locate the upstream or downstream position, disconnect the electrical plug, unscrew the old sensor and install the replacement with proper torque. After installation the vehicle’s ECU will re-learn oxygen readings; any stored diagnostic codes may need clearing.

• Direct-fit design for bolt-in replacement with factory harness
• Supplied as a two-piece set for systems requiring both sensors
• Clear existing OBD-II codes after replacement to complete diagnostics

What quality and support does AdvanEX provide?

AdvanEX provides aftermarket compatibility with attention to fit and function. The product listing includes an after-sales service provision — contact through the original seller channel for returns or refunds if the sensor doesn’t meet expectations.

• Manufactured to match common OE fitment and electrical connectors
• Sold as replacement pair for many GM systems that require two sensors
• Customer service available for returns or refunds through the sales platform

Who is this for: installers, DIY mechanics and fleet technicians who need a cost-effective, direct-fit oxygen sensor replacement for GM-platform vehicles. If you are swapping out a worn or failed upstream or downstream O2 sensor on Buick, Cadillac, Chevrolet, GMC, Isuzu, Saab, Saturn, Hammer, Oldsmobile or Pontiac models and your OEM part number matches one of the cross-referenced numbers listed, this AdvanEX 234-4337 set offers a practical replacement option. Always verify connector type and part number against your vehicle’s original sensor before ordering.