Delphi ES20421 Oxygen Sensor - Rear

Delphi ES20421 Heated Oxygen Sensor Overview

The Delphi ES20421 is a heated oxygen sensor designed for precise emission control in select BMW models. Engineered with a 4-wire configuration and a flat connector shape, this sensor ensures accurate readings and reliable performance in the rear left position of your vehicle's exhaust system.

• Heated oxygen sensor with 4 wires for efficient operation
• Flat connector shape for secure and easy installation
• Thread size of 18 x 1.5 mm compatible with specified BMW models
• Overall length of 765.0 mm to fit rear exhaust positions
• Includes oxygen sensor and instruction sheet for installation guidance

Technical Details and Compatibility

The Delphi ES20421 oxygen sensor is specifically designed for emission control systems requiring a heated sensor type. Its 4-wire design supports both sensor heating and signal transmission, improving sensor response time and accuracy. The flat connector shape facilitates a reliable electrical connection, reducing the risk of disconnection or corrosion. With a thread size of 18 x 1.5 mm and an overall length of 765.0 mm, this sensor fits the rear left position on various BMW models including the 135i, 335i, 528i, 535i, 640i, 740i, ActiveHybrid series, and X series SUVs. For exact position compatibility, refer to your vehicle’s specifications.

Applications and Problem Resolution

• Helps maintain optimal air-fuel mixture for efficient combustion
• Reduces harmful emissions by providing accurate oxygen level data
• Addresses issues such as poor fuel economy and rough idling
• Prevents check engine light triggers related to oxygen sensor faults
• Supports proper operation of catalytic converters and emission systems

Installation Notes and Tips

When installing the Delphi ES20421 oxygen sensor, ensure the vehicle is cool to avoid burns. Use the included instruction sheet for guidance on connector alignment and torque specifications. Verify the sensor’s position as rear left or rear according to your BMW model’s requirements. Avoid over-tightening the sensor to prevent thread damage. It is recommended to inspect wiring and connectors for corrosion or damage before installation.

Quality Assurance and Warranty

Delphi oxygen sensors are manufactured to meet OEM standards for durability and performance. The ES20421 part number undergoes rigorous testing to ensure reliable operation under various driving conditions. While specific warranty details may vary, Delphi typically offers coverage against manufacturing defects. Consult product documentation or your supplier for exact warranty terms.