Bosch 15270 Oxygen Sensor - Downstream

Bosch Validated Oxygen Sensor for Toyota Highlander

This Bosch Validated Oxygen Sensor is a specific-fit, narrow-band heated replacement for downstream use on select 2001-2003 Toyota Highlander models. Bosch 15270 is built to deliver accurate air-fuel-ratio feedback to the ECU for stable closed-loop operation and emissions control.

Key Features

• Fits 2001-2003 Toyota Highlander, downstream
• Bosch Validated Oxygen Sensor line for OE-style replacement applications
• Narrow-band heated oxygen sensor for faster warm-up and closed-loop response
• 4-wire design with rectangular male connector and blade terminals
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Specific fit with included wiring harness
• Steel finish with metal housing for underbody durability
• Part number 15270 for direct catalog identification

Product Details

Bosch 15270 uses a switching-type oxygen sensing element to measure exhaust oxygen content and send precise feedback to the engine control unit. Bosch’s validated oxygen sensor line builds on decades of OE development, including narrow-band planar sensor technology that improves light-off speed, lambda accuracy, and closed-loop operation. For Toyota Highlander downstream service, this sensor supports consistent combustion control under changing temperature and vibration conditions.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What It Helps Address

• Check engine light related to downstream oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Rough idle or unstable closed-loop fuel control
• Elevated emissions from a worn or slow-responding sensor
• Delayed sensor warm-up after cold starts

Installation Notes

Fits 2001-2003 Toyota Highlander, downstream. Confirm the threaded mounting location, connector shape, wire count, and harness length before installation. Use the 18 mm thread size and 22 mm hex specification to match the correct service tool. Inspect the exhaust bung and wiring routing for heat damage or corrosion before installing Bosch 15270.

Quality Assurance

Bosch draws on more than five decades of OE oxygen sensor development, and the Validated Oxygen Sensor line is supplied to the aftermarket with OE-proven design principles and durable materials for demanding thermal and vibration environments.