Denso 234-4751 Oxygen Sensor - Downstream

Denso 234-4751 Oxygen Sensor for Mazda Protege

Denso 234-4751 is a specific-fit heated oxygen sensor built for OE-style replacement on the 1999-2003 Mazda Protege, downstream position. It is engineered for accurate exhaust feedback, stable engine management, and a first-time fit on the listed application.

Denso’s OE Style line focuses on direct replacement parts built to match factory fit and function. This oxygen sensor uses a threaded mounting design, a female connector, 4-wire configuration, and a 34.65-inch wiring harness length for the specified Mazda Protege application.

Key Features

• OE Style replacement oxygen sensor for direct-fit service
• Heated sensor design for faster operating temperature
• Specific fit for 1999-2003 Mazda Protege, downstream
• 4-wire construction with female connector
• Threaded mounting type with 0.708-inch thread diameter
• 34.65-inch wiring harness length for the listed application

Detailed Description

The Denso 234-4751 oxygen sensor is designed for the downstream location on the 1999-2003 Mazda Protege. As part of Denso’s OE Style product line, it is precision built to match the original sensor’s fitment and electrical layout, helping restore proper exhaust monitoring and fuel control on the vehicle. Denso also incorporates an aluminum oxide trap layer to help protect the ceramic element from silicone and lead contamination, supporting long service life and consistent performance. This part cross-references Bosch 13885 and NTK 22510 for the same application.

What This Oxygen Sensor Helps Address

• Check engine light caused by a failing downstream oxygen sensor
• Incorrect exhaust feedback to the engine control system
• Reduced fuel economy from inaccurate air-fuel monitoring
• Rough or inconsistent engine operation related to sensor degradation
• Emissions test failure tied to a worn oxygen sensor

Installation Notes and Tips

Confirm the downstream sensor location before ordering and match the connector, wire count, and thread size to the original part. For Mazda Protege oxygen sensor replacement, inspect the harness routing and connector condition before installation, and verify the exhaust threads are clean before threading in the new sensor. Use the vehicle’s service procedure for proper torque and connector placement.

Quality Assurance

Denso manufactures and tests this oxygen sensor to OE standards for direct replacement use. The OE Style design is intended to deliver the correct fit and function for the listed Mazda Protege applications, including 1999-2003 Mazda Protege downstream service.