NTK 21517 Oxygen Sensor

Direct Fit Oxygen Sensor

NTK 21517 is a specific-fit heated oxygen sensor built for direct replacement applications. It uses a threaded mounting design and a 4-wire configuration with a 12.25-inch harness length for a clean OE-style installation.

Compatible with Buick, Pontiac, Chevrolet, and GMC applications that require an upstream or downstream oxygen sensor in the listed fitments, this NTK oxygen sensor is engineered for accurate air/fuel feedback and reliable emissions system operation. The 18 mm thread diameter and direct-fit design support proper sensor placement without guesswork.

Key Features

• Heated oxygen sensor for faster operating response
• Specific-fit design for direct replacement use
• Threaded mounting type with 18 mm thread diameter
• 4-wire configuration with 12.25-inch harness length
• NTK 21517 cross-references common OE-style applications

Detailed Description

NTK 21517 is part of the Direct Fit Oxygen Sensor line, a product family focused on application-specific coverage and OE-style replacement. NTK draws on its role as a major oxygen sensor manufacturer and uses ceramic-based sensor technology with manufacturing controls from raw material through finished product. The result is a sensor designed to match the fit, form, and function expected in emissions control service.

This part cross-references Bosch 15899 and DENSO Auto Parts 234-4646 for the same application. It is used in a range of Buick, Pontiac, Chevrolet, and GMC vehicles, including Buick Allure, Buick LaCrosse, and Pontiac Grand Prix applications listed as upstream sensors, along with select downstream applications in Chevrolet Astro and GMC Safari fitments. The NTK 21517 part number is also useful when searching for the correct direct-fit oxygen sensor for these vehicles.

What It Is Used For

• Replacing a failed oxygen sensor that triggers drivability or emissions faults
• Restoring accurate air/fuel ratio feedback to the engine control system
• Addressing slow sensor response or heater circuit issues
• Correcting check engine light conditions related to oxygen sensor performance
• Replacing an OE-style sensor with the correct threaded, specific-fit design

Installation Notes and Tips

Verify the exact position, bank, and sensor location against the vehicle listing before installation. Confirm the harness length, wire count, and threaded mounting style match the original sensor. The NTK 21517 is a direct-fit replacement, so it is intended to install in the listed application without universal adaptation.

Quality Assurance

NTK tests oxygen sensors during manufacturing to help ensure quality and reliability that meet or exceed OE specifications. The brand is part of the NGK family and is recognized for OE application coverage and sensor manufacturing expertise.