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NTK 25173 Oxygen Sensor - Downstream or Downstream Left
| Brand | NTK 25173 |
|---|---|
| Position | Downstream Left and Downstream |
| Wiring Harness Length | 38.2500 |
| Sensor Type | Heated |
| Universal Or Specific Fit | Specific |
| Wire Quantity | 4 |
| Thread Diameter | 18.000 |
| Mounting Type | Threaded |
| Product line | Direct Fit Oxygen Sensor |
| Fits | Audi · 6 vehicles |
Direct fit design. Built for specific replacement applications with OE-style fit, form, and function.
Heated sensor. Helps deliver faster operating response after startup.
OE supplier heritage. NTK draws on original equipment oxygen sensor manufacturing expertise.
Cross-references DENSO Auto Parts 234-4409, Quality-Built 13955 and 06E906265D for the same application. See all 4.
Direct Fit Oxygen Sensor for Audi Applications
The NTK 25173 is a direct fit heated oxygen sensor built for specific Audi applications. It uses a threaded mounting design and a 4-wire configuration with a 38.25-inch harness for a precise replacement path.
Key Features
- Direct fit oxygen sensor for specific applications
- Heated sensor design for faster operating response
- 4-wire construction
- Threaded mounting type
- 38.25-inch wiring harness length
- NTK 25173 part number for identification
Detailed Description
NTK 25173 is part of the Direct Fit Oxygen Sensor line, built to match OE-style fit, form, and function for import and domestic coverage. NTK draws on its role as a major original equipment oxygen sensor supplier and applies ceramic sensor expertise from raw material through finished product. This oxygen sensor is engineered for specific Audi fitments, including Audi A4, Audi A4 Quattro, Audi A6, and Audi A6 Quattro applications listed below. The NTK 25173 is a practical replacement choice when the original sensor needs to be restored to proper operation.
This part cross-references DENSO Auto Parts (e.g., 234-4409) for the same application.
What It Helps Fix
- Faulty oxygen sensor readings
- Check engine light concerns related to sensor performance
- Incorrect air-fuel mixture feedback
- Emissions system inspection failures tied to sensor output
- Slow sensor response from a worn heated sensor
Installation Notes and Tips
Fits 2010-2011 Audi A6, downstream. Fits 2009 Audi A6 Quattro, downstream left. Fits 2006 Audi A4, downstream left. Fits 2006 Audi A4 Quattro, downstream left. Fits 2005 Audi A4 Quattro, downstream left. Confirm the connector style, harness length, and threaded mounting location before installation. Use the vehicle’s listed chassis note where applicable, including the 2006 A4 and A4 Quattro chassis break.
Quality Assurance
NTK tests these oxygen sensors during manufacturing to meet or exceed OE specifications. The brand’s OE supplier background and ceramic sensor manufacturing process support consistent fit and reliable performance.
| Year | Make | Model | Liters | Cylinders | Position | Notes |
|---|---|---|---|---|---|---|
| 2011 | Audi | A6 | 3.2L | V6 | Downstream | Cyls. 4-6; B2S2; OE MFR: NTK; Direct Fit Oxygen Sensor |
| 2010 | Audi | A6 | 3.2L | V6 | Downstream | Cyls. 4-6; B2S2; OE MFR: NTK; Direct Fit Oxygen Sensor |
| 2009 | Audi | A6 Quattro | 3.0L | V6 | Downstream Left | Replacement oxygen sensor for B2S2 location.; Direct Fit Oxygen Sensor |
| 2006 | Audi | A4 | 3.2L | V6 | Downstream Left | To Chassis # 8E-6-035 000; OE MFR: NTK; Direct Fit Oxygen Sensor |
| 2006 | Audi | A4 Quattro | 3.2L | V6 | Downstream Left | To Chassis # 8E-6-035 000; OE MFR: NTK; Direct Fit Oxygen Sensor |
| 2005 | Audi | A4 Quattro | 3.2L | V6 | Downstream Left | Replacement oxygen sensor for B2S2 location.; Direct Fit Oxygen Sensor |
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