Bosch 18204 Oxygen Sensor - Upstream

Bosch Wideband Oxygen Sensor 18204

Bosch 18204 is a validated wideband air-fuel oxygen sensor built for precise upstream fuel-trim control. It delivers continuous lambda measurement for vehicles that rely on accurate feedback to manage fuel delivery, performance, and emissions.

Key Features

• Wideband A/F oxygen sensor for high-precision air-fuel ratio monitoring
• Heated design for faster sensor activation and stable operation
• Specific-fit replacement with 5-wire harness and square connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing and ceramic sensor construction for thermal durability
• Wiring harness included with 11.4 in harness length and 15.0 in overall length
• Upstream position application for OE-style engine management feedback

Product Details

This Bosch Validated Oxygen Sensor line is focused on OE-style accuracy and durability for modern engine control systems. Bosch pioneered the planar wideband pump-cell design used in current wideband sensing technology, and part number 18204 reflects that engineering approach with fast light-off, optimized heater control, and robust construction. It is a direct-fit replacement for select Honda and Acura applications, including Fits 2021-2025 Acura RDX, Upstream; Fits 2021-2025 Acura TLX, Upstream; Fits 2021-2022 Honda Accord, Upstream; Fits 2017-2022 Honda CR-V, Upstream; and Fits 2016-2021 Honda Civic, Upstream. This part cross-references 365315K8004 and 365316B2A01 for the same application.

What It Helps Address

• Incorrect air-fuel ratio readings from a worn upstream sensor
• Check engine lights related to oxygen sensor performance
• Rough idle, hesitation, or inconsistent throttle response caused by poor mixture control
• Reduced fuel economy from inaccurate feedback to the ECU
• Higher emissions from delayed or unstable sensor response

Installation Notes and Tips

Install Bosch 18204 in the upstream threaded sensor location specified for the vehicle application. Verify connector shape, terminal count, and harness routing before installation. Use the correct 18 mm oxygen sensor socket or wrench to avoid damaging the hex, and confirm the exhaust threads are clean before tightening. Because this is a specific-fit sensor, match the vehicle year, make, model, and position exactly before ordering.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development and aftermarket sensor engineering. The Bosch Validated Oxygen Sensor line is built to OE-proven standards for accurate signal output, reliable heater performance, and long-term service in demanding thermal conditions.