Bosch 18146 Oxygen Sensor - Downstream

Bosch Validated Oxygen Sensor for Downstream Use

Bosch 18146 is a specific-fit, narrow-band heated oxygen sensor built for downstream applications on select INFINITI and Nissan vehicles. It provides the ECU with air-fuel-ratio feedback needed for stable closed-loop control and emissions monitoring.

The Bosch Validated Oxygen Sensor line draws on Bosch OE development, including narrowband sensor designs that improve response time and lambda accuracy. Bosch 18146 uses a threaded metal housing, a 4-wire harness, and a rectangular male connector with female terminals for a direct replacement-style installation.

Key Features

• Specific-fit downstream oxygen sensor for select INFINITI Q50, INFINITI Q70, Nissan Versa, Nissan Versa Note, and INFINITI M35h applications
• Narrow-band heated oxygen sensor design for closed-loop fuel control
• 4-wire configuration with included wiring harness
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Rectangular connector, male connector gender, female terminal gender
• Bosch part number 18146 for catalog and cross-reference lookup

Product Details

Bosch 18146 is engineered as a standard replacement oxygen sensor for downstream placement, where it monitors exhaust oxygen content after the catalytic converter. That signal helps the engine control unit maintain the proper air-fuel ratio during normal operation. The Bosch Validated Oxygen Sensor platform reflects Bosch’s long OE development history, using ceramic sensing elements, controlled heater operation, and high-temperature materials for consistent performance under heat and vibration.

This part cross-references 226A01KT0A for the same application. Use Bosch 18146 when searching for a downstream oxygen sensor for 2014-2018 INFINITI Q50, 2014-2018 INFINITI Q70, 2012-2018 Nissan Versa, 2014-2016 Nissan Versa Note, 2017 Nissan Versa Note to 07/2017, and 2012-2013 INFINITI M35h applications.

What It Helps Address

• Fault codes related to downstream oxygen sensor performance
• Unstable closed-loop fuel control caused by a worn sensor
• Reduced emissions monitoring accuracy
• Slow sensor response from heat-related aging
• Driveability issues tied to incorrect exhaust oxygen readings

Installation Notes

Confirm the downstream location, connector shape, wire count, and thread size before installation. Bosch 18146 uses an 18 mm threaded mount, a 4-wire harness, and a 14.6 in overall length with a 13.4 in sealing-surface-to-connector measurement. Verify the vehicle build date on 2017 Nissan Versa Note models, since coverage applies only to units built to 07/2017.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE sensor development and aftermarket supply experience. The design uses durable materials and heater control strategies developed for demanding thermal and vibration conditions, supporting consistent signal output in everyday driving.