Bosch 13906 Oxygen Sensor - Upstream

Bosch Validated Oxygen Sensor for Lexus and Toyota

Bosch 13906 is a specific-fit, narrow-band heated oxygen sensor built for upstream air-fuel ratio monitoring. It provides the ECU with precise feedback for stable combustion control and emissions management on select Lexus SC300 and Toyota Supra applications.

The Bosch Validated Oxygen Sensor line reflects Bosch OE development in oxygen sensing, including ceramic sensing elements, controlled heater operation, and durable materials for consistent signal output under heat and vibration. Bosch 13906 is a direct replacement choice for drivers servicing a 1998 Toyota Supra upstream oxygen sensor or a 1998-2000 Lexus SC300 upstream oxygen sensor.

Key Features

• Part number: Bosch 13906
• Specific-fit oxygen sensor for confirmed applications
• Narrow-band heated sensor design
• Upstream position for air-fuel ratio feedback
• 4-wire harness with included wiring harness
• Blade terminals, rectangular connector, male connector and terminal ends
• Threaded mounting with 18 mm thread size and 22 mm hex size
• Metal housing for standard replacement service

Detailed Description

Bosch 13906 is engineered as a standard replacement oxygen sensor for vehicles that rely on narrow-band upstream feedback to manage fuel delivery and emissions. On the 1998 Toyota Supra and 1998-2000 Lexus SC300, this sensor monitors exhaust oxygen content ahead of the catalyst so the ECU can adjust mixture control during closed-loop operation. The heated design helps the sensor reach operating temperature faster, supporting quicker signal response after startup.

This Bosch Validated Oxygen Sensor uses a threaded mount, 18 mm thread diameter, and a 24.6 in overall length with a 20.3 in wiring harness length. The 4-wire configuration, rectangular connector, and blade terminals match the specified application requirements. Bosch 13906 also cross-references 8946514200 for the same application.

What It Helps Address

• Check engine light related to upstream oxygen sensor performance
• Rich or lean fuel trim conditions caused by inaccurate O2 feedback
• Slow closed-loop transition after cold start
• Unstable idle or drivability issues tied to air-fuel ratio control
• Emissions test failures linked to sensor response or signal degradation

Installation Notes and Tips

Verify the connector shape, wire count, thread size, and upstream location before installation. Use the confirmed fitment data for a 1998 Toyota Supra upstream oxygen sensor or a 1998-2000 Lexus SC300 upstream oxygen sensor, and confirm cylinder-specific application notes where listed. Inspect the exhaust bung threads and wiring routing before tightening the sensor to avoid harness strain or cross-threading.

Quality Assurance

Bosch has decades of OE oxygen sensor development behind this Validated Oxygen Sensor line, with designs based on proven narrow-band and heated sensor technology used to support accurate ECU feedback and durable service in demanding thermal conditions.