Bosch 13751 Oxygen Sensor - Downstream, Downstream Left or Upstream

Bosch Oxygen Sensor for OE-Style Emissions Control

Bosch 13751 is a narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It supports stable combustion control and lower emissions across changing engine loads, making it a direct-fit replacement for select Hyundai and Kia applications.

The Bosch Engineered Oxygen Sensor line draws on Bosch OE development, including the transition from early thimble-style sensors to faster-responding planar narrowband designs. This product line focuses on accurate lambda measurement, quicker closed-loop operation, and durable performance in high-heat, high-vibration environments.

Key Features

• Specific-fit oxygen sensor for direct replacement applications
• Narrow-band heated sensor design for faster operating temperature
• 4-wire configuration with square male connector and blade terminals
• Threaded mounting with 18 mm thread size and 22 mm hex size
• Wiring harness included for OE-style connection length and routing
• Metal housing and high-temperature-resistant construction
• Part number 13751 for catalog and service matching

Detailed Description

Bosch 13751 is engineered as a standard replacement oxygen sensor for vehicles that rely on narrow-band feedback to manage fuel delivery and emissions. It measures exhaust oxygen content and sends that signal to the ECU so the engine can maintain the correct air-fuel ratio during warm-up, cruise, and closed-loop operation. This helps preserve drivability and emissions performance on applications such as the Hyundai Sonata, Hyundai Santa Fe, Kia Optima, Kia Magentis, Kia Sedona, and Kia Soul.

Built with a heated sensing element, Bosch 13751 reaches operating temperature quickly and maintains stable signal output under demanding thermal conditions. The specific-fit design, threaded mount, and included harness support OE-style replacement on downstream and upstream locations listed in the fitment data. If you are replacing a worn sensor on a 2001-2006 Hyundai Sonata downstream application or a 2010-2011 Kia Soul upstream application, Bosch 13751 provides the correct sensor format for those vehicles.

This part cross-references Hyundai/Kia OE numbers 392102B040 and 3921038015 for the same application.

What It Helps Address

• Check engine light caused by oxygen sensor signal faults
• Rich or lean fuel trim conditions from inaccurate exhaust feedback
• Slow closed-loop response after startup
• Emissions test failures related to sensor performance
• Rough idle or drivability issues tied to air-fuel control

Installation Notes and Tips

Confirm the sensor position before ordering, since fitment includes upstream, downstream, and downstream left applications. Match the connector shape, wire count, and thread size to the original sensor, and inspect the harness routing before installation. Use the correct oxygen sensor socket for the 22 mm hex and verify the exhaust bung threads are clean before threading in the new sensor.

Compatible With 2010-2011 Kia Soul, upstream; 2001-2006 Hyundai Santa Fe, downstream; 2001-2006 Kia Magentis, downstream; 2001-2006 Kia Optima, downstream; 2002-2005 Hyundai Sonata, downstream; 2002-2005 Kia Sedona, downstream left; and 1999-2001 Hyundai Sonata, downstream with California Emission System.

Quality Assurance

Bosch has more than five decades of OE oxygen sensor development behind this product line. Bosch Engineered Oxygen Sensors are built to OE-proven standards for signal accuracy, heater control, and durability in demanding exhaust environments.