Denso 234-4339 Oxygen Sensor - Upstream

OE-Style Heated Oxygen Sensor

Denso 234-4339 is an OE-style heated oxygen sensor built for exact replacement and first-time fit. It is engineered for upstream applications on select Buick, Cadillac, Chevrolet, GMC, Isuzu, and Saab vehicles, including the Buick Lucerne, Cadillac DTS, and Chevrolet Trailblazer.

The Denso OE Style line focuses on direct-fit replacement parts that match factory specifications. This sensor uses a threaded mounting design, a female connector, 4 wires, and a 15.75-inch wiring harness for a clean installation on the correct upstream location.

Key Features

• Heated oxygen sensor for upstream exhaust monitoring
• Specific-fit design for direct replacement
• Threaded mounting type with 0.708-inch thread diameter
• 4-wire configuration with female connector
• 15.75-inch wiring harness length
• Built to OE standards for factory-style fit and function
• Aluminum oxide trap layer helps protect the ceramic element from silicone and lead contamination

Detailed Description

Denso 234-4339 is designed for drivers and technicians who need a direct-fit oxygen sensor that matches original equipment dimensions and connector layout. As part of Denso’s OE Style product line, this sensor is precision built for replacement use on upstream positions where accurate exhaust feedback is critical to engine management. It is a strong match for 2006-2011 Buick Lucerne, 2006-2011 Cadillac DTS, and 2007-2009 Chevrolet Trailblazer upstream applications, along with other listed GM and Saab platforms.

This part cross-references Bosch 15128 and NTK 21558 for the same application. The Denso 234-4339 also aligns with several OE and aftermarket numbers used on select GMC, Isuzu, and Saab vehicles.

Common Issues This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio feedback from a worn upstream sensor
• Reduced fuel economy caused by slow sensor response
• Rough idle or drivability concerns tied to exhaust feedback errors
• Failed emissions testing due to sensor-related fault codes

Installation Notes and Tips

Confirm the upstream sensor location and connector style before ordering. This part uses a specific-fit, threaded design, so matching the vehicle application and harness length is important for proper installation. Inspect the exhaust bung threads and connector condition before installation, and clear diagnostic trouble codes after replacement if required by the vehicle.

Compatible With 2006-2011 Buick Lucerne, Upstream; 2006-2011 Cadillac DTS, Upstream; 2007-2009 Chevrolet Trailblazer, Upstream; 2007-2009 GMC Envoy, Upstream; 2006-2009 Saab 9-7x, Upstream; 2006-2007 Buick Rainier, Upstream; 2006 Chevrolet SSR, Upstream; 2006 Chevrolet Trailblazer, Upstream; 2006 Chevrolet Trailblazer EXT, Upstream; 2006 GMC Envoy, Upstream; 2006 GMC Envoy XL, Upstream; 2006 Isuzu Ascender, Upstream.

Quality Assurance

Denso manufactures and tests this oxygen sensor to OE standards for consistent fit and performance. The design includes an aluminum oxide trap layer to help protect the sensing element from contamination, supporting long service life in demanding exhaust conditions.