Delphi ES10590 Oxygen Sensor - Front

Front Heated Oxygen Sensor for Subaru

The Delphi ES10590 is a front heated oxygen sensor built for precise exhaust monitoring on select Subaru applications. It uses a 3-wire design with a triangle connector and 18 x 1.5 mm thread size, making it a direct-fit option for vehicles that need accurate air-fuel feedback at the front sensor location.

Key Features

• Heated oxygen sensor for faster operating temperature
• 3-wire configuration for the listed Subaru applications
• Triangle connector shape for OE-style connection
• 18 x 1.5 mm thread size
• 425.0 overall length
• Front position fitment
• Package contents: oxygen sensor and instruction sheet

Detailed Description

Delphi ES10590 is an emission control sensor for front placement on 1996-1999 Subaru Legacy, 1998-1999 Subaru Forester, and 1998-1999 Subaru Impreza, including 1999 Subaru Impreza and 1999 Subaru Legacy without California Emission System. Delphi draws on OE heritage and supplier experience with major automakers, and that background is reflected in the sensor design and application coverage. This part cross-references DENSO Auto Parts 234-3091 and Walker Products 250-23091 for the same application. Search terms such as Subaru Forester front oxygen sensor, Subaru Impreza front O2 sensor, and Subaru Legacy front heated oxygen sensor apply to this part number ES10590.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings from a worn front sensor
• Slow sensor response during closed-loop operation
• Emission control faults tied to front exhaust monitoring
• Rough idle or drivability issues linked to inaccurate exhaust feedback

Installation Notes and Tips

Verify the front sensor location, connector shape, and thread size before installation. Confirm vehicle emissions configuration, especially for 1999 Subaru Impreza and 1999 Subaru Legacy models without California Emission System. Inspect the harness routing and connector condition before connecting the new sensor. Use the included instruction sheet during installation and ensure the sensor is tightened to the correct specification for the exhaust bung.

Quality Assurance

Delphi builds aftermarket parts using OE experience and knowledge developed through long-term supplier relationships with leading automakers. ES10590 is engineered for the listed Subaru fitments and emission control requirements.