Bosch 18273 Oxygen Sensor - Upstream or Upstream Left

Bosch OE Quality Oxygen Sensor 18273

Bosch 18273 is a narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It supports stable combustion control and emissions management for select GM trucks, SUVs, and vans, including Chevrolet Silverado 1500, Tahoe, and GMC Sierra 1500 applications.

The Bosch OE Quality Oxygen Sensor line builds on Bosch’s long history in oxygen-sensor development, including early thimble-style designs and later planar narrowband technology. This sensor uses advanced ceramic elements, optimized heater control, and high-temperature-resistant materials for consistent signal response under demanding thermal and vibration conditions.

• Part number: 18273
• Narrow-band heated oxygen sensor for upstream applications
• Specific-fit design with 4-wire, blade-terminal configuration
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included for direct replacement use
• Metal housing with oblong male connector
• OE-quality replacement for select Cadillac, Chevrolet, and GMC vehicles

Detailed Product Overview

Bosch 18273 is engineered as a standard replacement oxygen sensor for upstream locations where accurate exhaust-gas feedback is critical. It measures oxygen content in the exhaust stream and sends that data to the engine control unit so fuel delivery can be adjusted in closed-loop operation. That makes it a direct-fit service part for vehicles such as the Chevrolet Silverado 1500, GMC Sierra 1500, Cadillac Escalade, and related applications listed in the fitment data. If you are replacing a worn upstream sensor on a Chevrolet Tahoe or GMC Yukon, Bosch 18273 provides the OE-style sensor architecture expected for those applications.

This part cross-references GM OE numbers 12659516 and 12666612 for the same application.

What This Oxygen Sensor Helps Address

• Check engine light related to oxygen sensor performance
• Rough idle or unstable air-fuel control from a slow upstream sensor
• Reduced fuel control accuracy during closed-loop operation
• Emissions test failures tied to sensor response issues
• Delayed heater operation in heated narrow-band sensor circuits

Installation Notes and Tips

Confirm the sensor position before ordering, since this part is listed for upstream left and upstream locations depending on vehicle application. Verify connector shape, wire count, and thread size against the original sensor before installation. Use proper oxygen-sensor service tools for removal and installation, and inspect the harness routing to keep the lead away from exhaust heat and moving components.

Compatible With 2014-2018 Chevrolet Silverado 1500, Upstream; 2018 Chevrolet Silverado 2500 HD, Upstream; 2019 Chevrolet Silverado 1500 LD, Upstream; 2015 and 2016-2020 Chevrolet Tahoe, Upstream; 2016-2020 Chevrolet Express 2500 and Express 3500, Upstream; 2014-2018 GMC Sierra 1500, Upstream; 2018 GMC Sierra 2500 HD and Sierra 3500 HD, Upstream; 2019 GMC Sierra 1500 Limited, Upstream Left; 2015 and 2016-2020 GMC Yukon and Yukon XL, Upstream/Upstream Left; 2015 and 2016-2020 Cadillac Escalade and Escalade ESV, Upstream/Upstream Left.

Quality Assurance

Bosch backs this oxygen sensor with OE development experience and materials selected for durability in high-heat exhaust environments. The Bosch OE Quality Oxygen Sensor line is built to deliver consistent signal accuracy and heater performance for service replacement on select Cadillac, Chevrolet, and GMC vehicles.