NTK 21042 Oxygen Sensor - Downstream

Direct Fit Oxygen Sensor for OE Replacement

The NTK 21042 is a direct fit heated oxygen sensor built for specific downstream applications. It is engineered for import and domestic vehicles and uses a threaded mounting design with a 4-wire configuration for OE-style replacement.

Compatible with 2002-2005 Chevrolet Cavalier downstream, 2005 Pontiac Grand Am downstream, and 2002-2005 Pontiac Sunfire downstream, this sensor supports accurate exhaust feedback for the engine control system. The NTK Direct Fit Oxygen Sensor line focuses on fit, form, and function with application-specific coverage.

Key Features

• Part number: 21042
• Heated oxygen sensor for faster operating response
• Specific fit for direct replacement installation
• 4-wire design with 48.75 in. wiring harness length
• 18 mm threaded mounting type
• Downstream application coverage
• NTK OE-focused sensor design and manufacturing

Application Details

Fits 2002-2005 Chevrolet Cavalier, downstream. Fits 2005 Pontiac Grand Am, downstream. Fits 2002-2005 Pontiac Sunfire, downstream. This part cross-references Bosch 15903 and DENSO Auto Parts 234-4108 for the same application.

NTK’s Direct Fit Oxygen Sensor line is built around application-specific coverage and OE-style dimensions. As part of the NGK family of products, NTK applies ceramic sensor manufacturing expertise and extensive testing to support consistent signal output and reliable replacement performance. The 21042 is intended for drivers and repair shops replacing a downstream sensor on the listed Chevrolet and Pontiac models.

Common Problems This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Incorrect exhaust oxygen readings sent to the engine computer
• Slow sensor response after the engine reaches operating temperature
• Emissions test failures tied to downstream sensor faults
• Rough fuel control caused by a worn or contaminated sensor

Installation Notes

Verify the connector, wire count, thread diameter, and downstream location before installation. This is a specific-fit sensor, so match the vehicle year, make, model, and position to the listed applications. Inspect the exhaust bung threads and wiring routing during replacement to ensure proper seating and clearance.

Quality Assurance

NTK manufactures oxygen sensors to meet or exceed OE specifications and tests them during production for quality and reliability. The brand is recognized as a major original equipment oxygen sensor supplier, with coverage built for import and domestic applications.