NTK 21097 Oxygen Sensor - Upstream Left or Upstream Right

Direct Fit Oxygen Sensor for GM Applications

NTK 21097 is a direct fit, heated narrow-band oxygen sensor built for OE-style replacement on select Cadillac, Chevrolet, and GMC vehicles. It provides closed-loop feedback to the ECU to help maintain air-fuel control, support fuel efficiency, and monitor emissions system performance.

Compatible With 2014-2020 Cadillac Escalade, Chevrolet Tahoe, Silverado 1500, Express 2500, Express 3500, and GMC Yukon, Sierra 1500, Savana 2500, and Savana 3500 applications in upstream left or upstream right positions, depending on the vehicle.

Key Features

• NTK Direct Fit Oxygen Sensor, part number 21097
• Heated narrow-band sensor with switching zirconia technology
• Specific-fit design for OE-style replacement
• 4-wire configuration with blade terminals
• Oval female connector with 13.75 in. (350 mm) wiring harness length
• M18 x 1.5 thread size and 7/8 in. (22 mm) hex/wrench size
• Standard replacement grade for emissions control service

Product Details

NTK is a major OEM oxygen sensor manufacturer, and this sensor reflects that OE-focused engineering approach. The sensor supplies constant feedback to the engine control unit so the system can adjust the air-fuel ratio and monitor catalyst and fuel-delivery performance. The direct fit layout helps match the original connector style, thread size, and harness length for the listed GM trucks and SUVs. If you are replacing a failing upstream oxygen sensor on a 2016-2020 Chevrolet Tahoe or a 2014-2018 GMC Sierra 1500, NTK 21097 is built for the same application family.

This part cross-references DENSO Auto Parts (e.g., 234-4103, 234-4940) for the same application.

Common Problems This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings in closed-loop operation
• Reduced fuel economy caused by inaccurate exhaust feedback
• Emissions test failures tied to sensor response issues
• OBDII fault codes related to fuel delivery or catalytic converter efficiency

Installation Notes and Tips

Verify the vehicle’s upstream left or upstream right sensor location before ordering, since fitment varies by model and engine configuration. Confirm the connector shape, wire count, thread size, and harness length against the original sensor before installation. Use the listed 7/8 in. (22 mm) wrench size and M18 x 1.5 thread specification when matching the replacement to the factory mounting point.

Quality Assurance

NTK manufactures OEM oxygen sensors and controls the ceramic element process from raw material through finished product. That manufacturing focus supports consistent sensor response and OE application coverage for the listed Cadillac, Chevrolet, and GMC vehicles.