NTK 21055 Oxygen Sensor - Upstream

Direct Fit Oxygen Sensor for Malibu

NTK 21055 is a direct fit heated oxygen sensor built for specific applications, including the 2004-2006 Chevrolet Malibu. It uses a threaded mounting design, a 4-wire configuration, and a 9.75-inch wiring harness length for OE-style replacement on upstream Bank 1 Sensor 1 locations.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor is built around OE application coverage and precise fitment. NTK develops oxygen sensors with ceramic-based manufacturing control and extensive production testing to help maintain fit, form, and function that align with original equipment expectations.

• Direct fit oxygen sensor for specific vehicle applications
• Heated sensor design for upstream exhaust monitoring
• 4-wire configuration with 9.7500-inch harness length
• 18.000 thread diameter with threaded mounting type
• OE-style replacement for Chevrolet Malibu oxygen sensor service
• Cross-reference: Bosch 15899

Detailed Application and Function

NTK 21055 is an upstream oxygen sensor used to monitor exhaust oxygen content before the catalytic converter. On the 2006 Chevrolet Malibu, it fits Bank 1 Sensor 1. On the 2004-2005 Chevrolet Malibu, it fits the upstream B1S1 position for Z-Body, New Style applications. If you are searching for a 2006 Chevrolet Malibu upstream oxygen sensor or a 2004-2005 Chevrolet Malibu Bank 1 Sensor 1 replacement, this part number is the direct-fit option to verify.

What This Sensor Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio feedback at the engine control module
• Slow or inaccurate upstream exhaust readings
• Emissions test failures tied to sensor response issues
• Driveability concerns caused by a worn or contaminated sensor

Installation Notes and Tips

Confirm the vehicle year, engine configuration, and sensor position before ordering. This NTK 21055 oxygen sensor uses a threaded mount and 4-wire heated design, so match the connector routing and harness length to the original part. For best results, inspect the exhaust threads and wiring path before installation on Chevrolet Malibu applications.

Quality Assurance

NTK is a major original equipment oxygen sensor manufacturer with broad import and domestic coverage. Each sensor is manufactured and tested to meet or exceed OE specifications for quality and reliability, supporting consistent replacement performance on the Chevrolet Malibu and other listed applications.