Bosch 15973 Oxygen Sensor - Downstream

Bosch OE Oxygen Sensor for Nissan Downstream Applications

Bosch Actual OE Oxygen Sensor 15973 is a specific-fit, narrow-band heated sensor built for downstream use on select Nissan emissions systems. It provides the ECU with precise air-fuel-ratio feedback to support stable combustion control and lower exhaust emissions.

Key Features

• Specific-fit Bosch oxygen sensor for downstream placement
• Narrow-band heated design for faster closed-loop response
• 4-wire configuration with square male connector and blade terminals
• Threaded mounting with 18 mm thread size and 22 mm hex
• Wiring harness included for direct replacement service
• Metal housing and high-temperature materials for demanding exhaust conditions

Product Details

Built on Bosch’s OE oxygen sensor development history, this sensor uses a ceramic sensing element and controlled heater operation to improve signal stability during warm-up and normal driving. The narrow-band switching design is suited to downstream monitoring on emissions-equipped Nissan applications, including 2001-2004 Nissan Xterra downstream and 1998-2000 Nissan Frontier downstream with California Emission System. It also fits 2000 Nissan Xterra downstream with California Emission System. Bosch 15973 is a practical OE-style replacement when accurate sensor feedback and consistent heater performance are required.

This part cross-references 226A03S666 for the same application.

What It Helps Address

• Check engine lights related to oxygen sensor performance
• Delayed closed-loop operation after startup
• Unstable air-fuel ratio feedback to the ECU
• Emissions test failures tied to downstream sensor faults
• Rough combustion control caused by aging sensor response

Installation Notes and Tips

Confirm the downstream sensor location before ordering, since this part is specific to the listed Nissan applications. Match the 4-wire connector, threaded mount, and 18 mm thread size to the original sensor. Inspect the harness routing and exhaust-side connector condition during replacement, and verify there is no thread damage in the bung before installation.

Quality Assurance

Bosch supplies OE-developed oxygen sensor technology to the aftermarket, using durable materials, optimized heater control, and narrow-band sensing for consistent operation under heat and vibration. The Bosch Actual OE Oxygen Sensor line is built to OE-level specifications for direct replacement service.