NTK 21545 Oxygen Sensor

NTK Direct Fit Oxygen Sensor 21545

NTK 21545 is a direct fit heated oxygen sensor built for specific applications that require OE-style fit, form, and function. It is engineered for import and domestic vehicles and is backed by NTK’s focus on ceramic sensor technology and original equipment coverage.

For Chevrolet Express, GMC Savana, Buick Rainier, Chevrolet Trailblazer, and related applications, this sensor supports accurate exhaust monitoring with a threaded, specific-fit design.

Key Features

• Heated oxygen sensor for faster operating response
• Specific fit design for direct replacement applications
• 4-wire configuration with a 17.75 in. wiring harness
• 18 mm thread diameter with threaded mounting type
• OE-equivalent design for select upstream and downstream positions
• NTK Direct Fit Oxygen Sensor line is built for streamlined coverage and application matching

Product Details

NTK Part Number 21545 is part of the Direct Fit Oxygen Sensor line, created to simplify replacement selection while maintaining OE-style performance. NTK manufactures oxygen sensors with ceramic expertise and extensive testing during production to help ensure consistent quality and reliability. This sensor is listed for multiple GM applications, including 2003-2007 Chevrolet Express and GMC Savana models, plus 2006 Buick Rainier, Chevrolet Trailblazer, GMC Envoy, Isuzu Ascender, and Saab 9-7x positions. It is also cross-referenced to Bosch 15894 for the same application.

Common Issues This Sensor Addresses

• Check engine light related to oxygen sensor circuit faults
• Incorrect air-fuel ratio readings from a worn upstream sensor
• Slow sensor response affecting fuel control and emissions monitoring
• Failed downstream monitoring on emissions-equipped vehicles
• Replacement needs for damaged or aging OE-style oxygen sensors

Installation Notes and Tips

• Verify the exact year, make, model, and sensor position before ordering.
• Confirm whether the vehicle uses upstream right, downstream right, downstream left, or upstream left placement.
• Check connector style and harness routing against the original sensor.
• Inspect the exhaust threads and mounting location before installation.
• Clear diagnostic trouble codes after installation and confirm proper sensor operation.

Quality Assurance

NTK is the world’s largest supplier and manufacturer of original equipment oxygen sensors. Part number 21545 is manufactured and tested to meet or exceed OE specifications for fit and reliability across listed applications.