Bosch 18104 Oxygen Sensor - Downstream or Upstream

Bosch Wideband Oxygen Sensor for Hyundai and Kia

Bosch Validated Oxygen Sensor 18104 is a specific-fit wideband air-fuel ratio sensor for select Hyundai and Kia applications. It delivers continuous, high-precision AFR feedback to the ECU, helping maintain accurate mixture control across changing load and temperature conditions.

Built with a heated design, 5-wire harness, threaded mounting, and a 22 mm hex, this Bosch oxygen sensor is made for direct replacement service on upstream and downstream positions where listed.

Key Features

• Wideband A/F oxygen sensor for precise air-fuel ratio measurement
• Heated sensor with optimized heater control for faster light-off
• Specific-fit design with included wiring harness
• 5-wire configuration with 6 terminals and blade-style terminals
• Threaded mounting, 18 mm thread diameter, 22 mm hex size
• Metal housing with robust ceramic construction for thermal durability
• Overall length: 17.9 in; sealing surface to connector end: 16.7 in

Product Details

Bosch 18104 is part of the Bosch Validated Oxygen Sensor line, a product line focused on OE-style replacement for modern engine management systems. Bosch pioneered the wideband A/F oxygen sensor design, and this sensor uses that same measurement approach to provide detailed feedback across the full lambda range. That makes it a practical choice for vehicles that need accurate fuel control for emissions compliance, drivability, and fuel efficiency.

This part cross-references Hyundai/Kia OE numbers 392102G100 and 392102G720 for the same application. It is commonly searched as a Bosch 18104 oxygen sensor for Hyundai Sonata, Kia Optima, and Kia Sportage applications.

What This Sensor Helps Address

• Check engine lights related to oxygen sensor performance
• Rough idle or inconsistent air-fuel mixture control
• Reduced fuel economy caused by inaccurate exhaust feedback
• Emissions test failures tied to sensor response issues
• Slow sensor switching or delayed ECU correction on wideband systems

Installation Notes

• Verify upstream or downstream position before ordering; fitment varies by vehicle and emission package.
• Confirm connector shape, terminal count, and harness length against the original sensor.
• Use the correct 18 mm oxygen sensor socket or 22 mm hex tool for removal and installation.
• Inspect the exhaust bung threads and wiring routing before final tightening.
• Fits 2013-2016 Hyundai Santa Fe Sport, Upstream.
• Fits 2011-2016 Kia Optima, Upstream.
• Fits 2011-2016 Kia Sportage, Upstream.
• Fits 2011-2015 Hyundai Sonata, Upstream.
• Fits 2014-2015 Hyundai Tucson, Downstream.
• Fits 2010-2014 Hyundai Sonata, Downstream, with California Emission System.
• Fits 2011-2014 Kia Sorento, Upstream.
• Fits 2014 Kia Sportage, Upstream, Located on Bottom.
• Fits 2014 Kia Sportage, Upstream, Installed at top.
• Fits 2010-2013 Hyundai Tucson, Upstream, with California Emission System.
• Fits 2010-2013 Kia Forte, Upstream, with California Emission System.
• Fits 2010-2013 Kia Forte Koup, Upstream, with California Emission System.
• Fits 2012-2013 Kia Forte5, Upstream, with California Emission System.
• Fits 2011-2013 Kia Optima, Downstream.
• Fits 2011-2013 Kia Optima, Upstream, with California Emission System.
• Fits 2011-2013 Kia Sportage, Upstream, with California Emission System.
• Fits 2010-2012 Hyundai Santa Fe, Upstream.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development in emission control and engine management components. The Bosch Validated Oxygen Sensor line is built to deliver OE-proven fit and measurement accuracy for select Hyundai and Kia vehicles, including Sonata, Optima, and Sportage applications.