NTK 21061 Oxygen Sensor - Downstream Left or Downstream Right

NTK Direct Fit Oxygen Sensor for OE Replacement

NTK 21061 is a direct fit heated oxygen sensor built for specific applications that require OE-style fit, form, and function. It is engineered for downstream positions on select Cadillac CTS, Chevrolet Silverado 3500 HD, GMC Sierra 3500 HD, and Hummer H2 models, with application coverage spanning 2008-2015.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor is made for straightforward replacement on vehicles that need a threaded, 4-wire heated sensor with the correct harness length and connector-style application match.

Key Features

• Part number: 21061
• Heated oxygen sensor for downstream use
• Specific fit for select GM and Hummer applications
• 4-wire design with 21.75 in. wiring harness length
• 18 mm thread diameter and threaded mounting type
• OE-style fit, form, and function for direct replacement service

Product Details

NTK is known for oxygen sensor manufacturing and ceramic technology used from raw material control through finished production. The 21061 direct fit oxygen sensor is manufactured and tested to meet or exceed OE specifications, supporting accurate replacement on vehicles such as the Cadillac CTS, Chevrolet Silverado 3500 HD, GMC Sierra 3500 HD, and Hummer H2. This part number 21061 is also cross-referenced to Bosch 15165 for the same application.

Compatible applications include Fits 2009-2015 Cadillac CTS, Downstream Right; Fits 2009-2015 Cadillac CTS, Downstream Left; Fits 2008-2010 Chevrolet Silverado 3500 HD, Downstream Left; Fits 2008-2010 GMC Sierra 3500 HD, Downstream Left; Fits 2009 Hummer H2, Downstream Right; and Fits 2009 Hummer H2, Downstream Left.

What This Sensor Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect downstream air-fuel feedback readings
• Slow sensor response from a worn heated O2 sensor
• Emissions test failures tied to sensor degradation
• Replacement needs after sensor contamination or age-related wear

Installation Notes and Tips

Verify the connector, harness length, thread diameter, and sensor position before installation. This is a specific-fit, threaded heated oxygen sensor, so matching the exact downstream left or downstream right location is important for proper service. Confirm vehicle application by year, make, model, and position before ordering.

Quality Assurance

NTK manufactures oxygen sensors with extensive testing during production to support reliability and OE-level performance. The brand’s OE application focus and sensor specialization make the 21061 a practical replacement choice for service work on covered Cadillac, Chevrolet, GMC, and Hummer applications.