NTK 24578 Oxygen Sensor - Downstream

Direct Fit Oxygen Sensor for Subaru Applications

NTK Oxygen Sensor 24578 is a specific-fit, heated downstream sensor built for select Subaru Forester and Subaru Impreza applications. It uses an OE-equivalent design to support accurate exhaust feedback in vehicles from 1999 through 2004.

As part of NTK’s Direct Fit Oxygen Sensor line, this replacement sensor is built for straightforward application matching, with the correct threaded mounting style, 4-wire configuration, and 18.25-inch wiring harness length.

Key Features

• Direct Fit Oxygen Sensor for specific Subaru applications
• Heated oxygen sensor design for downstream placement
• 4-wire configuration with threaded mounting type
• 18.000 thread diameter and 18.2500 wiring harness length
• OE-equivalent design for Subaru Forester and Subaru Impreza
• NTK part number 24578

Product Details

NTK 24578 is engineered for downstream use on 1999-2004 Subaru Forester and 1999-2004 Subaru Impreza, with a 1999 Subaru Impreza Federal Emissions B1S2 application also listed. This oxygen sensor is part of NTK’s Direct Fit Oxygen Sensor line, which focuses on application-specific replacement parts that match original equipment fit, form, and function. NTK is a major original equipment oxygen sensor manufacturer, and its sensors are extensively tested during production to help maintain quality and reliability that meet or exceed OE specifications.

This part cross-references Bosch 13469 for the same application.

What This Sensor Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect downstream exhaust gas feedback readings
• Emissions test failures tied to sensor response issues
• Rough idle or drivability concerns caused by faulty sensor input
• Fuel control problems linked to aging or contaminated sensors

Installation Notes and Tips

Confirm the vehicle’s year, model, and downstream sensor position before ordering. This NTK 24578 sensor uses a threaded mounting style and a 4-wire heated design, so connector and harness routing should be matched to the original sensor layout on the Subaru Forester or Subaru Impreza application.

For best results, compare the original sensor’s connector, wire count, and harness length before installation. The part number 24578 is intended for specific-fit replacement use, not universal application.

Quality Assurance

NTK develops oxygen sensors with ceramic technology control from raw material through finished product, and its OE manufacturing background supports consistent fit and performance. The Direct Fit Oxygen Sensor line is built to provide OE-style replacement coverage for import and domestic vehicles, including Subaru Forester and Subaru Impreza applications.