Delphi ES10439 Oxygen Sensor - Front or Rear

Delphi ES10439 Oxygen Sensor Overview

The Delphi ES10439 is a heated oxygen sensor built for emission control service on select Subaru applications. It combines OE-based engineering with a round connector, 3-wire design, and 18 x 1.5 mm thread size for a direct-fit replacement on listed vehicles.

Compatible with 1995 Subaru Legacy, front; 1995-1998 Subaru Legacy, rear; 1995-1997 Subaru Impreza, front; and 1995-1997 Subaru Impreza, rear. If you are searching for a Subaru Legacy oxygen sensor or a Subaru Impreza oxygen sensor, ES10439 is the part number to verify against your application.

Key Features

• Heated oxygen sensor for faster operating temperature and emissions feedback
• 3-wire construction with round connector shape
• 18 x 1.5 mm thread size for listed Subaru exhaust locations
• Overall length: 450.0
• Includes oxygen sensor and instruction sheet
• OE heritage backed by Delphi’s 100 years of original-equipment experience

Detailed Description

Delphi ES10439 is engineered for emission control systems that rely on accurate exhaust oxygen readings to manage fuel delivery and catalyst performance. Delphi draws on long-standing OE supplier experience, so the sensor reflects original-equipment knowledge in an aftermarket replacement format. This part cross-references DENSO Auto Parts 234-3088 for the same application.

Use ES10439 when servicing Subaru Legacy and Subaru Impreza models listed in the fitment data. The heated design helps the sensor reach operating temperature quickly, which supports stable feedback during cold starts and normal driving. The round connector and 3-wire layout help match the factory-style electrical connection on the specified front and rear positions.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel mixture readings
• Reduced catalyst efficiency monitoring
• Rough idle or drivability issues tied to exhaust feedback
• Failed emissions inspection caused by sensor faults

Installation Notes and Tips

Verify the position before ordering, since this part is listed for front and rear locations depending on the vehicle. Confirm the thread size, connector shape, wire count, and overall length against the original sensor before installation. For the exact position specific to your Subaru Legacy or Subaru Impreza, refer to the application tab and vehicle build details.

Quality Assurance

Delphi builds this oxygen sensor using OE-based engineering and supplier knowledge developed over a century of original-equipment experience. That background supports consistent fitment and function for emission control service on the listed Subaru applications.