NTK 21524 Oxygen Sensor - Downstream

Direct-fit oxygen sensor

NTK oxygen sensor 21524 is a specific-fit, heated sensor built for downstream applications. It uses a threaded mounting design with a 25-inch harness and 4-wire configuration for a direct replacement approach.

Key features

• Direct Fit Oxygen Sensor line for application-specific replacement
• Heated sensor design for faster operating response
• 4-wire construction with 25-inch wiring harness
• Threaded mounting with 18 mm thread diameter
• OE-equivalent design for downstream use

Detailed description

NTK 21524 is part of the Direct Fit Oxygen Sensor line and is engineered for specific applications rather than universal use. It is a heated downstream oxygen sensor with a threaded mount, 18 mm thread diameter, and a 25-inch harness, making it a fitment-focused replacement for emissions control service. This part cross-references Bosch 13041 and DENSO Auto Parts 234-4648 for the same application. Compatible vehicles include Chevrolet Metro, Suzuki Swift, Pontiac Firefly, Geo Metro, Chevrolet Tracker, and Suzuki Vitara in downstream positions. For buyers searching for a downstream oxygen sensor for Chevrolet Metro or Suzuki Swift applications, NTK 21524 provides an OE-style replacement path with application-specific coverage.

What it is used for

• Replacing a worn downstream oxygen sensor that can affect emissions monitoring
• Addressing sensor faults that trigger check engine light diagnostics
• Restoring proper exhaust feedback for fuel control system operation
• Servicing vehicles that require a threaded, heated, specific-fit sensor

Installation notes and tips

Confirm the downstream location, connector style, wire count, and thread size before installation. Match the harness length and mounting type to the original sensor on the vehicle. Use the fitment notes to verify California emissions applications where listed.

Quality assurance

NTK is part of the NGK family of products and is a major original equipment oxygen sensor supplier. Each sensor is extensively tested during manufacturing to meet or exceed OE specifications for fit, form, and function.