NGK 21549 Oxygen Sensor, 4-Wire Heated O2 Sensor, 18mm Thread

The NGK (NTK) 21549 oxygen sensor, also called an O2 sensor or air/fuel ratio sensor, is an OE-identical direct-fit replacement. It monitors the oxygen in your exhaust and sends that signal to the engine computer, which uses it to keep the air/fuel mixture correct. A healthy sensor helps the catalytic converter last longer, lowers emissions and supports good fuel economy.

Key Features:

• Four-wire, heated design with a threaded 18mm body
• Wire length of about 15 in. (380mm)
• OE-type connector for plug-in installation, with no cutting or splicing
• Dual-coated platinum element for long life and fast response
• Ceramic sensing element with an integrated heater that reaches operating temperature quickly. This gives faster closed-loop activation and lower cold-start emissions.
• Corrosion-resistant housing protects the ceramic element from silicone and lead poisoning
• Porous PTFE filter lets atmospheric oxygen in while keeping out water and engine contaminants
• Each sensor goes through a multi-step test process for quality and durability

Specifications:

• Manufacturer part number: 21549
• Thread diameter: 18mm
• Number of wires: 4
• Heated: Yes
• OEM references: GM 12572705, 12617332
• Interchange numbers: ACDelco 213-1161, Denso 234-4669, Bosch 15282, Delphi ES20008, BWD OS1820, Spectra Premium OS5056, SMP SG1066, CARQUEST 75-2537

This sensor is built to OE standards within close tolerances. That helps the vehicle stay compliant with emissions testing and keeps the engine running efficiently.