Delphi ES20003 Oxygen Sensor - Rear

Rear Heated Oxygen Sensor for OE-Style Emissions Control

The Delphi ES20003 is a rear heated oxygen sensor built for precise exhaust monitoring in compatible GM applications. It uses a 4-wire design with a square connector and 18 x 1.5 mm thread size, making it a direct-fit style replacement for select Chevrolet, Oldsmobile, and Pontiac vehicles.

Delphi draws on OE experience and supplier knowledge developed over decades of original-equipment service, bringing that engineering background into this aftermarket oxygen sensor. The ES20003 is a rear-position sensor with an overall length of 1140.0 and includes an instruction sheet for installation reference.

Key Features

• Heated oxygen sensor for rear exhaust monitoring
• 4-wire configuration for stable signal operation
• Square connector shape for application-specific fitment
• 18 x 1.5 mm thread size
• Overall length: 1140.0
• Package contents: oxygen sensor and instruction sheet
• Delphi ES20003 part number for ordering and cross-reference

Detailed Description

The Delphi ES20003 oxygen sensor is engineered for rear sensor locations in vehicles that rely on accurate exhaust feedback to manage emissions performance. It is a heated sensor, which helps it reach operating temperature more quickly for consistent readings after startup. This part number, ES20003, is commonly searched for rear oxygen sensor replacement on applications such as the Chevrolet Corvette, Chevrolet Malibu, Oldsmobile Alero, Pontiac Grand Am, and Oldsmobile Cutlass.

This part cross-references Bosch 13111 and DENSO Auto Parts 234-4617 for the same application. Delphi’s OE heritage and manufacturing background support the sensor’s fit and function expectations for service replacement work.

What It Helps Address

• Check engine light concerns related to rear oxygen sensor faults
• Incorrect exhaust oxygen readings affecting emissions monitoring
• Slow sensor response after startup
• Rough idle or drivability issues tied to faulty exhaust feedback
• Failed emissions inspection caused by a worn rear sensor

Installation Notes and Tips

• Verify rear sensor placement before ordering; this ES20003 is for the rear position.
• Confirm connector shape, wire count, and thread size match the original sensor.
• Inspect the exhaust bung threads before installation to ensure proper seating.
• Use the included instruction sheet as a reference during replacement.
• Clear diagnostic trouble codes after installation and confirm proper sensor operation.

Quality Assurance

Delphi builds this oxygen sensor using OE-based engineering knowledge developed through long-term supplier experience with major automakers. That background supports consistent replacement quality for emissions control service on compatible Chevrolet, Oldsmobile, and Pontiac applications.