NTK 21044 Oxygen Sensor - Downstream

Direct Fit Oxygen Sensor for OE Replacement

The NTK 21044 is a direct fit heated oxygen sensor built for specific downstream applications. It is engineered for precise fit, stable signal performance, and OE-style installation on select Chevrolet, GMC, Buick, Pontiac, Isuzu, Saab, and Oldsmobile vehicles.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor reflects the brand’s focus on application-specific coverage and OE application technology for import and domestic vehicles.

Key Features

• Heated oxygen sensor for downstream exhaust monitoring
• Specific-fit design for direct replacement installation
• 4-wire configuration with a 12.2500-inch wiring harness
• 18.000 thread diameter with threaded mounting type
• Built to meet or exceed OE specifications through manufacturing testing
• OE-style replacement for select 2002-2008 GM and related applications

Detailed Description

NTK part number 21044 is a direct fit oxygen sensor designed for downstream placement and OE-style service replacement. It uses a heated sensor design to support accurate exhaust feedback after the catalytic converter, helping maintain proper emissions system operation on the listed vehicles. This sensor is a strong match for buyers searching for a downstream oxygen sensor for 2006-2008 Chevrolet Malibu, 2002-2005 Chevrolet Trailblazer, or 2002-2005 GMC Envoy applications.

NTK is known for oxygen sensor manufacturing and ceramic technology control from raw material through finished product. That manufacturing focus supports consistent fit, form, and function across the NTK 21044 application range. This part cross-references Bosch 15894 for the same application.

What It Helps Address

• Check engine light related to downstream oxygen sensor faults
• Incorrect air-fuel feedback from a worn or slow-responding sensor
• Emissions test failures tied to oxygen sensor performance
• Rough exhaust monitoring after catalytic converter service
• Replacement needs for damaged wiring or sensor connector issues

Installation Notes and Tips

Verify the vehicle’s engine and sensor position before ordering. This part is listed for downstream use only and should be matched to the exact application shown in the fitment data. The threaded mounting design and 4-wire layout should be checked against the original sensor before installation. For best results, inspect the exhaust threads and wiring route during replacement to ensure proper seating and harness clearance.

Quality Assurance

NTK manufactures oxygen sensors with extensive testing during production to support quality and reliability that meet or exceed OE specifications. The brand’s OE-focused engineering and application coverage make the NTK 21044 a dependable replacement choice for select GM, Isuzu, Saab, and Oldsmobile vehicles.

Compatible Vehicles

• Fits 2006-2008 Chevrolet Malibu, downstream
• Fits 2006-2007 Pontiac G6, downstream
• Fits 2004-2005 Buick Rainier, downstream
• Fits 2004-2005 Chevrolet Colorado, downstream
• Fits 2004-2005 Chevrolet Malibu, downstream
• Fits 2002-2005 Chevrolet Trailblazer, downstream
• Fits 2002-2005 Chevrolet Trailblazer EXT, downstream
• Fits 2004-2005 GMC Canyon, downstream
• Fits 2002-2005 GMC Envoy, downstream
• Fits 2002-2005 GMC Envoy XL, downstream
• Fits 2004-2005 GMC Envoy XUV, downstream
• Fits 2003-2005 Isuzu Ascender, downstream
• Fits 2005 Saab 9-7x, downstream
• Fits 2002-2004 Oldsmobile Bravada, downstream