Bosch 15406 Oxygen Sensor - Downstream

Bosch Validated Oxygen Sensor for Civic

Bosch 15406 is a narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It is a specific-fit replacement for 2001-2005 Honda Civic downstream applications, helping maintain stable combustion control and lower emissions.

Key Features

• Specific-fit Bosch Validated Oxygen Sensor for 2001-2005 Honda Civic, downstream
• Narrow-band heated design for faster closed-loop operation
• 4-wire configuration with rectangular female connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included; harness length measures 20.6 in.
• Metal housing and high-temperature-resistant construction for demanding exhaust conditions

Product Details

Bosch 15406 uses advanced ceramic sensing elements and optimized heater control to deliver consistent signal response across changing exhaust temperatures. As part of the Bosch Validated Oxygen Sensor line, it reflects Bosch’s long OE development history in oxygen sensing technology, including narrowband planar designs that improve light-off speed and closed-loop transition time. This makes Bosch 15406 a practical replacement for Honda Civic downstream sensor service where accurate mixture feedback is needed. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Common Issues This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Unstable air-fuel ratio feedback to the ECU
• Delayed closed-loop operation after startup
• Increased exhaust emissions from a worn downstream sensor
• Rough combustion control caused by inaccurate sensor output

Installation Notes and Tips

Verify downstream placement before installation and confirm the connector shape, wire count, and thread size match the original sensor. Use the correct oxygen sensor socket for the 22 mm hex, and inspect the harness routing so the lead is kept away from exhaust heat and moving components. Bosch 15406 is a direct-fit style replacement for the listed Honda Civic applications, so matching the original connector and mounting style is important for proper installation.

Quality Assurance

Bosch draws on more than five decades of OE oxygen sensor development, and the Validated Oxygen Sensor line is built to OE-proven standards for accuracy, durability, and thermal resistance.