Bosch 13643 Oxygen Sensor - Downstream

Bosch Oxygen Sensor for Lexus IS300

Bosch 13643 is a specific-fit, narrow-band heated oxygen sensor built for precise air-fuel ratio feedback to the ECU. It is a downstream replacement for the 2001 Lexus IS300 and supports stable closed-loop fuel control under changing exhaust temperatures.

Key Features

• Specific-fit Bosch Engineered Oxygen Sensor for direct application matching
• Narrow-band heated O2 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
• Metal housing and high-temperature materials for demanding exhaust conditions
• Wiring harness included with 25.4 in harness length
• Downstream placement for the 2001 Lexus IS300, cylinder(s) 1, 2, and 3

Product Details

Bosch 13643 is part of the Bosch Engineered Oxygen Sensor line, which builds on Bosch OE development in oxygen sensing technology. Bosch introduced its original oxygen sensor design in 1976 and later advanced to planar narrowband construction for quicker light-off, improved lambda measurement, and faster transition into closed-loop operation. This Bosch 13643 oxygen sensor uses a heated narrow-band design to deliver consistent exhaust feedback for the 2001 Lexus IS300 downstream application, helping the engine management system maintain accurate fuel control.

This part cross-references 8946553110 for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Delayed closed-loop operation after startup
• Rough idle or drivability issues tied to exhaust sensor signal loss
• Elevated emissions from inaccurate downstream sensor readings

Installation Notes

Compatible With 2001 Lexus IS300, downstream. Verify connector shape, wire count, thread size, and sensor location before installation. Use the threaded mounting point and ensure the exhaust bung threads are clean and undamaged. Because this is a heated narrow-band sensor, confirm the harness routing keeps the lead away from exhaust heat and moving components.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development and aftermarket supply experience. The design reflects Bosch’s focus on durable ceramic sensing elements, controlled heater performance, and materials selected for high thermal and vibration loads.