NTK 21059 Oxygen Sensor - Downstream Left or Downstream Right

Direct-Fit Oxygen Sensor for GM Applications

NTK Oxygen Sensor 21059 is a direct-fit heated oxygen sensor built for specific downstream locations on select Chevrolet, GMC, Hummer, and Saab vehicles. It uses a 4-wire design with a 15-inch wiring harness, 18 mm thread diameter, and threaded mounting for OE-style replacement service.

Key Features

• Heated oxygen sensor for downstream right and downstream left positions
• Specific-fit design for direct replacement on listed applications
• 4-wire configuration with 15.0000 wiring harness length
• 18.000 thread diameter and threaded mounting type
• OE-style fit, form, and function for emission control service
• Cross-references Bosch 15282 and DENSO Auto Parts 234-4243 for the same application

Product Details

NTK part number 21059 is part of the Direct Fit Oxygen Sensor line, created for straightforward replacement in emission control systems. NTK applies ceramic manufacturing expertise and OE application coverage to produce sensors with controlled material quality from raw input through finished component. This oxygen sensor is engineered for specific downstream positions on vehicles such as the Chevrolet Express 2500, GMC Savana 3500, and Chevrolet Colorado, helping maintain accurate exhaust monitoring on supported GM platforms. The NTK 21059 is also listed for the GMC Canyon, Hummer H3, Hummer H3T, Chevrolet Trailblazer, GMC Envoy, and Saab 9-7x in the confirmed downstream locations.

What This Sensor Helps Address

• Check engine light related to downstream oxygen sensor faults
• Incorrect oxygen sensor signal in the exhaust monitoring system
• Emissions test failures tied to sensor performance
• Rough idle or drivability concerns caused by faulty exhaust feedback
• Replacement needs after sensor aging, contamination, or wiring wear

Installation Notes and Fitment

• Fits 2016 Chevrolet Express 2500, downstream right
• Fits 2016 Chevrolet Express 2500, downstream left
• Fits 2016 Chevrolet Express 3500, downstream right
• Fits 2016 Chevrolet Express 3500, downstream left
• Fits 2016 GMC Savana 2500, downstream right
• Fits 2016 GMC Savana 2500, downstream left
• Fits 2016 GMC Savana 3500, downstream right
• Fits 2016 GMC Savana 3500, downstream left
• Fits 2008-2015 Chevrolet Express 2500, downstream right
• Fits 2008-2015 Chevrolet Express 2500, downstream left
• Fits 2008-2015 Chevrolet Express 3500, downstream right
• Fits 2008-2015 Chevrolet Express 3500, downstream left
• Fits 2008-2015 GMC Savana 2500, downstream right
• Fits 2008-2015 GMC Savana 2500, downstream left
• Fits 2008-2015 GMC Savana 3500, downstream right
• Fits 2008-2015 GMC Savana 3500, downstream left
• Fits 2008-2014 Chevrolet Express 1500, downstream right
• Fits 2008-2014 Chevrolet Express 1500, downstream left
• Fits 2008-2014 GMC Savana 1500, downstream right
• Fits 2008-2014 GMC Savana 1500, downstream left
• Fits 2009-2012 Chevrolet Colorado, downstream right
• Fits 2009-2012 Chevrolet Colorado, downstream left
• Fits 2009-2012 GMC Canyon, downstream right
• Fits 2009-2012 GMC Canyon, downstream left
• Fits 2008-2010 Hummer H3, downstream right
• Fits 2008-2010 Hummer H3, downstream left
• Fits 2009-2010 Hummer H3T, downstream right
• Fits 2009-2010 Hummer H3T, downstream left
• Fits 2008-2009 Chevrolet Trailblazer, downstream right
• Fits 2008-2009 GMC Envoy, downstream right
• Fits 2008-2009 Saab 9-7x, downstream right

Before installation, confirm the connector style, downstream position, and thread size match the original sensor on your vehicle. For Chevrolet Express 2500 and GMC Savana 3500 applications, verify whether the sensor location is downstream right or downstream left before ordering.

Quality Assurance

NTK is a major original equipment oxygen sensor manufacturer with extensive manufacturing testing to support OE-level specifications for fit, form, and function. Part number 21059 reflects that OE-focused approach for service on supported Chevrolet, GMC, Hummer, and Saab applications.