Denso 234-4446 Oxygen Sensor - Downstream

Denso OE Style Oxygen Sensor 234-4446

Denso 234-4446 is an OE Style heated oxygen sensor built for direct replacement in specific Subaru applications. It is engineered for accurate exhaust feedback, stable engine management, and a first-time fit on select Subaru Legacy, Outback, and Impreza models.

The OE Style line focuses on exact replacement dimensions and connector fitment, making it a practical choice for drivers servicing a downstream sensor on Subaru Legacy, Subaru Outback, or Subaru Impreza applications.

Key Features

• Heated oxygen sensor for faster operating response
• Specific fit design for direct replacement
• 4-wire configuration with male connector
• Threaded mounting type with 0.708 in. thread diameter
• 27.17 in. wiring harness length
• Built to OE standards for fit and function
• Uses Denso’s aluminum oxide trap layer to help protect the sensing element from silicone and lead contamination

Detailed Description

Denso 234-4446 is a downstream oxygen sensor designed for select 2002-2009 Subaru vehicles. It is a heated, threaded sensor with a specific-fit design, making it suitable for direct replacement where the original sensor location and connector style must match. This part cross-references Bosch (e.g., 15025) for the same application.

As part of Denso’s OE Style product line, this sensor is manufactured and tested to OE-level standards and built for exact replacement fitment. The design supports accurate exhaust monitoring and helps maintain proper fuel control on Subaru Legacy, Subaru Outback, and Subaru Impreza applications that require a downstream oxygen sensor.

What It Helps Address

• Check engine light related to downstream oxygen sensor faults
• Incorrect air-fuel feedback from a worn sensor
• Reduced fuel economy caused by slow sensor response
• Rough idle or drivability issues tied to exhaust feedback errors
• Fitment problems from a sensor that does not match the OE connector or thread pattern

Installation Notes and Tips

Verify the vehicle year, model, and downstream position before ordering. This part fits 2005-2009 Subaru Legacy, downstream; 2005-2009 Subaru Outback, downstream; 2004-2005 Subaru Legacy, downstream, Calif.; loc. after primary catalyst; and 2004-2005 Subaru Outback, downstream, Calif.; loc. after primary catalyst; plus 2002 Subaru Impreza, downstream. Confirm the connector style, thread diameter, and harness length against the original sensor before installation.

For best results, inspect the exhaust threads and wiring routing during replacement. Denso 234-4446 is a direct-fit sensor, so proper vehicle identification is the key step before installation.

Quality Assurance

Denso manufactures this oxygen sensor to strict OE standards and tests it for replacement fit and performance. The OE Style design is intended to deliver the correct part and the correct fit for the listed Subaru applications.