Bosch 15988 Oxygen Sensor - Upstream, Upstream Left or Upstream Right

Bosch Wideband Oxygen Sensor for Lexus and Toyota

Bosch Validated Oxygen Sensor 15988 is a direct-fit wideband air-fuel ratio sensor for select Lexus and Toyota applications. It provides the ECU with continuous, high-precision air-fuel data across the full lambda range for accurate mixture control, stable drivability, and lower emissions.

Built with a heated design, threaded mounting, and a 4-wire harness with a rectangular male connector, this Bosch Validated Oxygen Sensor is made for upstream locations on vehicles such as the Toyota 4Runner, Toyota FJ Cruiser, and Lexus IS250. Part number 15988 is a standard replacement for specific OE-style applications where precise sensor feedback matters.

Key Features

• Wideband A/F oxygen sensor for continuous air-fuel ratio measurement
• Heated sensor design for faster response and stable operation
• Specific-fit replacement with included wiring harness
• 4-wire configuration with blade terminals and rectangular male connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing for durable underhood service
• Bosch Validated Oxygen Sensor line for OE-style replacement coverage

Product Details

Bosch pioneered the wideband A/F oxygen sensor design used in modern engine management, and this Bosch Validated Oxygen Sensor 15988 reflects that OE development background. The sensor measures air-fuel ratio continuously rather than switching at a narrow point, giving the engine control unit more detailed feedback during acceleration, cruising, and load changes. That makes it a strong choice for Lexus LS460, Lexus GX460, Toyota Land Cruiser, and other upstream applications listed in the fitment data.

This part cross-references OE numbers such as 894670C010 and 8946730030 for the same application.

What It Helps Address

• Check engine lights related to upstream air-fuel sensor performance
• Rough idle or inconsistent fuel mixture control
• Reduced fuel economy caused by inaccurate sensor feedback
• Emissions test failures tied to oxygen sensor faults
• Slow sensor response during load changes or cold starts

Installation Notes

Fits 2005-2007 Toyota Sequoia, upstream; 2005-2006 Toyota Tundra, upstream; 2007-2008 Toyota 4Runner, upstream; 2008-2009 Toyota FJ Cruiser, upstream; 2008-2011 Toyota Land Cruiser, upstream; 2008-2010 Toyota Highlander, upstream right; 2008-2013 Lexus GX460, upstream; 2008-2011 Lexus LX570, upstream; 2008-2012 Toyota 4Runner, upstream; 2009-2012 Lexus IS250, upstream left/right; 2009-2012 Lexus IS350, upstream left/right; 2009-2011 Lexus GS350, upstream left/right; 2010-2013 Lexus LS460, upstream right; 2010-2012 Lexus HS250h, upstream; 2014-2017 Lexus LS460, upstream.

Confirm the exact engine bank and sensor position before installation. Use the threaded mount and connector style to verify match-up with the original sensor, and inspect the harness routing so the lead length and connector orientation align with the factory layout.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development and aftermarket sensor engineering. The validated design, robust ceramic construction, and optimized heater control support reliable operation in demanding thermal conditions.