NGK 21544 Oxygen Sensor 4-Wire Heated Thread-In O2 Sensor

The NGK 21544 oxygen sensor (also called an O2 sensor or lambda sensor) is an OE-grade replacement that monitors exhaust gas oxygen content. It sends voltage signals to the engine management system so the air/fuel ratio can be adjusted for efficiency, lower emissions and good fuel economy. NGK is the manufacturer behind the NTK oxygen sensor line.

Key Features:

• Heated, 4-wire design with a 0-1 V output
• Thread-in mounting with an 18 mm thread diameter
• Factory-fitted OE-style connector with a wiring harness of about 16.75 in. for plug-and-play installation
• Thimble-type ceramic sensing element with an integrated heater, which reaches operating temperature quickly for faster closed-loop activation and reduced cold-start emissions
• Platinum-coated element for durability
• Corrosion-resistant housing that helps protect the ceramic element from silicone and lead poisoning
• Porous PTFE filter that lets atmospheric oxygen reach the sensor while keeping out water and engine contaminants
• Individually tested during manufacturing for quality and reliability

Cross-References: Replaces or interchanges with ACDelco AFS98, GM 19178928, DENSO 234-4025, Bosch 13444, Standard Motor Products SG274, Delphi ES10010 / ES10119 / ES20002 / ES20051, BWD OS840 / OS1072, Spectra Premium OS5209 and CARQUEST 75-1909.

A new oxygen sensor helps restore proper fuel control, supports emissions compliance and can help clear related check-engine light codes.