Delphi ES20323 Oxygen Sensor - Rear

Delphi ES20323 Rear Oxygen Sensor

The Delphi ES20323 is a heated rear oxygen sensor built for precise exhaust monitoring on select Toyota applications. It draws on Delphi’s OE heritage and decades of supplier experience to deliver the fit and signal characteristics expected in an aftermarket replacement.

• Heated oxygen sensor for rear position applications
• 4-wire design with square connector shape
• Thread size: 18 x 1.5 mm
• Overall length: 300.0
• Package contents: oxygen sensor and instruction sheet
• Fits 1995-1999 Toyota Avalon, rear

Fitment and Application

Compatible With 1995-1999 Toyota Avalon rear exhaust sensor locations, this Delphi ES20323 is specified for the rear position on those model years. If you are searching for a rear oxygen sensor for a 1995 Toyota Avalon, 1996 Toyota Avalon, 1997 Toyota Avalon, 1998 Toyota Avalon, or 1999 Toyota Avalon, this part number is the direct fitment reference to verify.

This part cross-references Bosch 13056 and DENSO Auto Parts 234-4061 for the same application.

How It Works

As a heated oxygen sensor, the ES20323 helps monitor exhaust oxygen content after the catalytic converter so the engine control system can evaluate emissions performance and fuel control strategy. The 4-wire configuration and square connector shape support a straightforward replacement on the specified Toyota Avalon rear location.

Common Issues It May Address

• Check engine light related to rear oxygen sensor performance
• Fault codes tied to slow sensor response or heater circuit concerns
• Incorrect exhaust feedback readings from a worn sensor
• Emissions test failures caused by degraded rear sensor output
• Restoration of proper rear O2 sensor signal on Toyota Avalon models

Installation Notes

Verify thread size, connector shape, wire count, and rear position before installation. Compare the removed sensor to the Delphi ES20323 and confirm the vehicle is a 1995-1999 Toyota Avalon with the rear sensor location specified in the fitment data. Follow the included instruction sheet and inspect the harness routing and connector condition during replacement.

Quality Assurance

Delphi builds this replacement part using OE experience and supplier knowledge developed through work with major automakers. That background is reflected in the ES20323’s application-specific design and replacement-focused construction for the rear oxygen sensor position.