NGK 21044 Oxygen Sensor 4-Wire Heated Downstream O2 Sensor

The NGK 21044 oxygen sensor (also called an O2 sensor or air-fuel ratio sensor) is a direct-fit replacement sensor from NGK/NTK, a major supplier of original equipment oxygen sensors. It monitors the oxygen content of the exhaust and sends feedback to the engine control unit. This helps the ECU manage the air-fuel ratio, maintain engine performance, improve fuel efficiency and reduce harmful emissions.

Key Features:

• Sensor type: Heated, 4-wire design with a 0-1 V voltage range
• Placement: Downstream (post-catalytic converter) position
• Mounting: Thread-in, 18 mm thread diameter
• Wiring: Wiring harness included, approximately 12.25 in. long
• Sensing element: Advanced ceramic element with a contaminant-resistant plasma jet and deposit trap overcoat to help protect against element poisoning
• Construction: Durable, corrosion- and abrasion-resistant build
• Fit: Direct-fit design for straightforward installation
• Bung: Oxygen sensor bung not included

A failing oxygen sensor can trigger the check-engine light and cause poor fuel economy or higher emissions. Replacing it with a quality NGK/NTK sensor helps restore proper closed-loop fuel control. Cross-references include GM 12578624, Isuzu 8125786240, Standard Motor Products SG1412, SG1619, SG1826 and SG706, and BWD OS2245.