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Bosch 15121 Oxygen Sensor - Downstream Left
| Brand | Bosch 15121 |
|---|---|
| Position | Downstream Left |
| Wiring Harness Length | 37.4 |
| Terminal Type | Blade |
| Universal Or Specific Fit | Specific |
| Wire Quantity | 4 |
| Grade Type | Standard replacement |
| Connector Shape | Rectangle |
| Terminal Quantity | 4 |
| Connector Gender | Male |
| Terminal Gender | Male |
| Overall Length | 41.1 |
| Mounting Type | Threaded |
| Automotive Color / Finish | Steel |
| Automotive Item Weight (lbs) | 0.308647 lb |
| Heated (Oxygen Sensor) | Yes |
| Hex Size (Oxygen Sensor) | 22 mm |
| Housing Material | Metal |
| Length (Sealing Surface To End Of Connector) | 40 in |
| Mounting Bracket Included | No |
| Oxygen Sensor Type | Narrow-band heated |
| Sensor Type | Narrow-band |
| Thread Diameter (Oxygen Sensor) | 18 mm |
| Thread Size | 18 |
| Wiring Harness Included | Yes |
| Product line | Bosch Validated Oxygen Sensor |
| Fits | Lexus · 1 vehicle |
Standard replacement. A direct-fit oxygen sensor for straightforward service replacement.
Narrow-band heated. Provides precise air-fuel readings and quicker closed-loop response.
OE-proven quality. Backed by Bosch's decades of oxygen sensor development.
Cross-references 8946530720 and 8946530830 for the same application. See all 2.
Bosch Validated Oxygen Sensor for Lexus GS300
Bosch Validated Oxygen Sensor 15121 is a specific-fit, narrow-band heated O2 sensor built for precise air-fuel-ratio feedback to the ECU. It is listed for the 2006 Lexus GS300, downstream left, and uses a threaded mounting design with a 4-wire harness for direct replacement service.
Key Features
- Specific-fit Bosch oxygen sensor for the 2006 Lexus GS300, downstream left
- Narrow-band heated sensor for closed-loop fuel control
- 4-wire design with included wiring harness and rectangular male connector
- Threaded mounting with 18 mm thread diameter and 22 mm hex size
- Standard replacement grade for emission control service
- Metal housing and high-temperature-resistant construction for demanding exhaust conditions
Product Details
Bosch Part Number 15121 is part of the Bosch Validated Oxygen Sensor line, which draws on Bosch OE development in oxygen sensing technology. This sensor uses a switching-type narrow-band design to report exhaust oxygen content to the engine control unit, helping maintain stable combustion control and emissions performance. For drivers and technicians servicing a 2006 Lexus GS300, downstream left, Bosch 15121 provides the correct fitment format for a direct replacement oxygen sensor service. This part cross-references Monroe Shocks & Struts (e.g., 8946530720, 8946530830) for the same application.
What This Sensor Helps Address
- Check engine light related to oxygen sensor performance
- Incorrect air-fuel ratio feedback to the ECU
- Rough idle or unstable closed-loop fuel control
- Elevated exhaust emissions from a worn downstream sensor
- Slow sensor response caused by heat cycling and vibration exposure
Installation Notes and Tips
Confirm the downstream left location on the 2006 Lexus GS300 before installation. Match the 4-wire connector, threaded mount, 18 mm thread size, and 22 mm hex size to the original sensor. Inspect the harness routing and connector condition during replacement, and verify the exhaust threads are clean before installing the new sensor.
Quality Assurance
Bosch has more than five decades of OE oxygen sensor development behind this product line, and the Validated Oxygen Sensor range is built to deliver OE-proven fit and performance for emission control service.
| Year | Make | Model | Drive Type | Liters | Cylinders | Position | Notes |
|---|---|---|---|---|---|---|---|
| 2006 | Lexus | GS300 | AWD | 3.0L | V6 | Downstream Left | Bosch Validated Oxygen Sensor |
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