Denso 234-5139 Air / Fuel Ratio Sensor - Upstream or Upstream Left

Overview of the Denso OE Style Air/Fuel Ratio Sensor

The Denso OE Style Air/Fuel Ratio Sensor 234-5139 is engineered for precise emissions control in select BMW and Mercedes-Benz vehicles. Designed as a heated sensor with a specific fit, it ensures accurate air-fuel mixture readings to optimize engine performance and reduce emissions.

• Heated sensor type for faster response times
• Specific fitment for BMW and Mercedes-Benz models
• 60.43-inch wiring harness length for proper installation
• Five-wire configuration with male connector
• Thread diameter of 0.711 inches for secure mounting
• Regular grade type for reliable operation

Detailed Product Description

This Denso Air/Fuel Ratio Sensor, part number 234-5139, belongs to the OE Style product line, which focuses on delivering original equipment quality and fitment. The OE Style line is designed to meet or exceed factory specifications, providing a direct replacement that maintains the integrity of your vehicle's emissions system. This sensor features a heated element to ensure quicker activation and more consistent readings under various operating conditions.

The sensor’s 60.43-inch wiring harness length and five-wire setup with a male connector are tailored for specific BMW and Mercedes-Benz models, including popular vehicles such as the BMW 1 Series M, 128i, 135i, 3 Series variants (323i, 325i, 328i, 330i, 335i), 5 Series models (525i, 528i, 530i), and Mercedes-Benz models like the CLK63 AMG, E320, X3, X5, and Z4. The 0.711-inch thread diameter ensures a secure and proper fit in the exhaust system.

Common Applications and Issues Addressed

• Helps maintain optimal air/fuel mixture for efficient combustion
• Reduces emissions by providing accurate sensor data to the engine control unit
• Prevents engine performance issues related to faulty air/fuel ratio readings
• Resolves check engine light triggers related to sensor malfunction
• Improves fuel economy by ensuring proper sensor operation

Installation Notes and Tips

• Ensure compatibility with your specific BMW or Mercedes-Benz model before installation
• Handle the sensor carefully to avoid damage to the heated element and wiring harness
• Use appropriate tools to avoid damaging the 0.711-inch threaded fitting
• Follow vehicle manufacturer torque specifications when installing the sensor
• Verify connector polarity and secure connection to prevent electrical issues

Quality Assurance and Warranty

Denso’s OE Style Air/Fuel Ratio Sensor 234-5139 is manufactured to meet original equipment standards, ensuring reliable performance and durability. While specific warranty details may vary, Denso products typically come with a limited warranty covering defects in materials and workmanship. This sensor is designed to provide consistent operation within the emissions control system of compatible BMW and Mercedes-Benz vehicles.