Delphi ES20066 Oxygen Sensor - Rear

Delphi ES20066 Rear Oxygen Sensor

The Delphi ES20066 is a heated rear oxygen sensor built for precise exhaust monitoring on select Mazda Miata applications. It combines OE heritage with application-specific fitment details to support accurate sensor replacement on 1996-1997 and 1999-2000 Mazda Miata models.

Key Features

• Heated oxygen sensor for rear position applications
• 4-wire design with square connector shape
• 18 x 1.5 mm thread size
• Overall length: 530.0
• Package contents: oxygen sensor and instruction sheet
• Direct-fit replacement for select Mazda Miata rear sensor locations

Product Details

Delphi ES20066 is engineered from Delphi’s OE experience and aftermarket knowledge, bringing a service replacement option for rear oxygen sensor locations. It is compatible with 1996-1997 Mazda Miata, rear, and 1999-2000 Mazda Miata, rear, without California Emission System. This part cross-references DENSO Auto Parts (e.g., 234-4145, 234-4333) for the same application. The heated, 4-wire configuration and square connector help match the original sensor layout on these Mazda Miata applications, while the 18 x 1.5 mm thread size supports proper exhaust bung fitment.

What It Helps Address

• Check engine light related to rear oxygen sensor performance
• Slow or inaccurate exhaust oxygen readings
• Emissions inspection failures tied to sensor output
• Rough fuel control caused by a worn rear sensor
• Replacement needs after sensor aging or contamination

Installation Notes

Verify rear sensor placement and connector style before installation. Confirm thread size and overall length against the original part, and inspect the harness routing so the 4-wire lead is not strained. For 1999-2000 Mazda Miata, this listing applies to rear applications without California Emission System. Follow the included instruction sheet and use proper exhaust sensor removal practices to avoid damaging the bung or wiring.

Quality Assurance

Delphi draws on more than a century of OE experience and supplier knowledge from top automakers, with OE heritage built into its aftermarket parts. That background supports consistent fitment and service replacement confidence for the Delphi ES20066.