Bosch 17357 Oxygen Sensor - Upstream or Upstream Left

Bosch Wideband OE Oxygen Sensor

Bosch 17357 is an Actual OE wideband air-fuel oxygen sensor built for precise mixture feedback and stable engine management. It uses a heated, specific-fit design with a 5-wire harness and 6-terminal connection for direct replacement service on select Audi and Volkswagen applications.

The Bosch Actual OE Oxygen Sensor line focuses on OE-proven sensor response, robust ceramic construction, and fast light-off performance. Bosch pioneered the wideband planar pump-cell design used in modern engine control, and this sensor follows that OE development approach for accurate air-fuel ratio measurement across the full lambda range.

Key Features

• Wideband A/F oxygen sensor for continuous air-fuel ratio measurement
• Heated design for faster operating temperature and stable signal output
• Specific-fit replacement with included wiring harness
• 5-wire configuration with oblong male connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing with OE-style construction for emission control service
• Overall length: 29.5 in; harness length: 26.2 in

Detailed Description

Bosch 17357 is a standard replacement wide band oxygen sensor for emission control repair where accurate upstream air-fuel feedback is required. It is listed for 2002-2004 Volkswagen Passat, upstream left; 2004-2006 Volkswagen Touareg, upstream; 2005-2006 Audi A8 Quattro, upstream; and 2007 Audi A8 Quattro, upstream for cylinders 4, 5, and 6. This part cross-references 1K0998262H for the same application. If you are searching for a Bosch 17357 oxygen sensor for Audi A8 Quattro or a Bosch 17357 wideband sensor for Volkswagen Touareg, this OE-style replacement matches the specified fitment and connector layout.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings from a worn upstream sensor
• Rough idle or drivability issues tied to poor mixture control
• Reduced fuel economy caused by inaccurate sensor feedback
• Emission test failures linked to faulty wideband sensor operation

Installation Notes and Tips

Verify the upstream sensor location, connector shape, terminal count, and thread size before installation. This sensor uses a threaded mount with an 18 mm thread diameter and a male oblong connector, so matching the original harness and bung specification is important. For best results, inspect the wiring route and connector condition during replacement on Audi A8 Quattro, Volkswagen Touareg, and Volkswagen Passat applications.

Quality Assurance

Bosch backs this sensor with more than five decades of OE development experience in oxygen sensing and engine management. The Actual OE Oxygen Sensor line is built to OE-proven standards used by vehicle manufacturers, with wideband measurement capability and durable construction for demanding thermal conditions.