Delphi ES20393 Oxygen Sensor - Rear

Delphi ES20393 Rear Oxygen Sensor

The Delphi ES20393 is a heated rear oxygen sensor built for precise exhaust monitoring and reliable replacement service. It draws on Delphi’s OE experience and supplier background, with aftermarket engineering informed by original equipment knowledge.

• Heated oxygen sensor for rear exhaust position
• 4-wire design for stable signal performance
• Square connector shape for direct-fit style replacement
• 18 x 1.5 mm thread size
• Overall length: 385.0
• Package contents: oxygen sensor and instruction sheet

Fitment and Application

Compatible with 1995-1998 Mazda Protege, rear, and 1995-1997 Kia Sephia, rear. This Delphi ES20393 oxygen sensor is also a cross-reference for DENSO Auto Parts 234-4140 and Walker Products 250-24292 for the same application.

Detailed Product Overview

Built as a heated rear oxygen sensor, the ES20393 is used to monitor exhaust oxygen content after the catalytic converter. That data helps the engine control system evaluate emissions performance and maintain proper fuel management. For drivers searching for a rear oxygen sensor for Mazda Protege or Kia Sephia models, Delphi ES20393 provides the key fitment and connector specifications needed for replacement selection.

Common Issues This Part May Address

• Check engine light related to rear O2 sensor performance
• Slow or inaccurate oxygen sensor signal response
• Emissions test failure caused by sensor degradation
• Rough fuel control feedback from a worn exhaust sensor
• Corrosion or connector wear at the rear sensor location

Installation Notes and Tips

Verify the rear position, 4-wire configuration, square connector, and 18 x 1.5 mm thread size before installation. Inspect the harness routing and connector condition, and confirm the sensor length matches the original layout on the vehicle. For best results, compare the old sensor to the new unit before threading it into the exhaust.

Quality Assurance

Delphi builds this replacement part using OE-focused engineering backed by more than a century of original equipment experience and supplier knowledge. That background is reflected in the ES20393’s fitment-specific design for rear oxygen sensor service on Mazda Protege and Kia Sephia applications.