Denso 234-9128 Air / Fuel Ratio Sensor - Upstream or Upstream Left

OE Style Air/Fuel Ratio Sensor for Toyota and Lexus

The Denso 234-9128 is an OE Style heated air/fuel ratio sensor built for exact replacement and first-time fit. It is engineered to match factory specifications for vehicles that need precise upstream fuel control and emissions feedback.

Compatible With select Toyota and Lexus applications, including 2012-2018 Toyota Avalon upstream, 2012-2017 Toyota Camry upstream, and 2013-2018 Lexus ES300h upstream. This Denso 234-9128 sensor also covers additional upstream and upstream left positions across supported models.

Key Features

• Heated air/fuel ratio sensor for upstream exhaust monitoring
• Specific fit design for direct replacement on listed applications
• 4-wire configuration with a 16.34 in. wiring harness length
• OE Style construction for factory-like fit and connector alignment
• Built to Denso’s OE-level testing and manufacturing standards
• Cross-references Bosch 18071 and NTK 24828 for the same application

Detailed Description

Denso 234-9128 is a regular-grade, heated air/fuel ratio sensor designed for precise upstream feedback in the engine management system. As an OE Style replacement, it is precision-built to match the original sensor form and function, helping maintain accurate air-fuel monitoring on Toyota and Lexus vehicles such as the Camry, Avalon, and ES300h. The specific-fit design supports proper installation on the listed positions without modification.

This sensor is intended for applications that require a direct-fit upstream replacement with factory-style wiring and connector layout. It is a practical choice when replacing a worn or slow-responding sensor on 2012-2018 Toyota Avalon, 2012-2017 Toyota Camry, or 2013-2018 Lexus ES300h models.

Common Issues This Part May Address

• Check engine light related to upstream air/fuel ratio sensor performance
• Rough idle or inconsistent fuel control caused by a failing sensor
• Reduced fuel economy from inaccurate exhaust feedback
• Slow sensor response affecting engine management readings
• Emissions test failure tied to sensor degradation

Installation Notes and Tips

Verify the vehicle year, engine configuration, and sensor position before ordering. This part is listed for upstream and upstream left locations only, with fitment varying by model and year. Confirm connector style, harness routing, and mounting location against the original sensor before installation. For best results, inspect the exhaust threads and wiring path during replacement.

Quality Assurance

Denso manufactures and tests this sensor to OE standards for consistent replacement quality and proper fit. The OE Style line is focused on direct replacement parts that match factory requirements for supported Toyota and Lexus applications.