Bosch 17078 Oxygen Sensor - Upstream

Bosch Wideband A/F Oxygen Sensor for Audi

Bosch Part Number 17078 is an Actual OE Oxygen Sensor built for precise air-fuel ratio monitoring in modern engine management systems. This wideband sensor provides fast, continuous feedback to the ECU, helping maintain accurate mixture control on Audi performance and luxury applications.

Compatible With 2013-2018 Audi A8 Quattro, Upstream; 2014-2018 Audi RS7, Upstream; 2013-2018 Audi S6, Upstream; 2013-2018 Audi S7, Upstream; and 2013-2018 Audi S8, Upstream.

Key Features

• Wideband A/F oxygen sensor for full lambda-range measurement
• Heated design for faster sensor activation and stable operation
• Specific fit with 5-wire configuration and included wiring harness
• Threaded mounting with 18 mm thread size and 22 mm hex size
• Oblong male connector with blade terminals
• Robust metal housing and ceramic sensor construction
• Standard replacement grade for OE-style service

OE-Style Air-Fuel Control

Bosch 17078 uses wideband sensing technology to deliver detailed air-fuel ratio data across the operating range, not just at a narrow switching point. That gives the ECU the information needed for accurate fuel control during idle, acceleration, cruising, and rapid load changes. Bosch pioneered the planar pump-cell wideband design used in modern engine management, and this Actual OE Oxygen Sensor reflects that OE development background for Audi A8 Quattro, RS7, S6, S7, and S8 upstream applications.

This part cross-references Bosch OE application 4H0906262N for the same application.

Common Issues This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings from a worn upstream sensor
• Rough idle or inconsistent throttle response caused by inaccurate feedback
• Reduced fuel economy from poor mixture control
• Higher emissions from delayed or unstable sensor response

Installation Notes

Install in the upstream position only where specified by the vehicle application. Verify the 18 mm thread size, 22 mm hex size, 5-wire connector layout, and harness length before installation. Because this is a specific-fit sensor, confirm connector routing and sensor location on the Audi A8 Quattro, RS7, S6, S7, or S8 before replacement.

Quality Assurance

Bosch supplies OE-proven oxygen sensors backed by more than five decades of original equipment development. This part is built to the same standard expected in modern emission control systems and is engineered for reliable operation through heat cycling and changing engine loads.