Bosch 17303 Oxygen Sensor - Upstream or Upstream Left

Bosch Wideband O2 Sensor for Mercedes-Benz

Bosch 17303 is an Actual OE Oxygen Sensor built as a wideband air-fuel sensor for precise mixture feedback to the ECU. It uses a heated, specific-fit design with a 5-wire harness and 6-terminal connection to support accurate control on Mercedes-Benz SLK55 AMG and SLK350 applications.

Key Features

• Wideband A/F oxygen sensor for continuous air-fuel ratio measurement across the full lambda range
• Heated design for faster sensor activity and stable operation during cold starts
• Specific fit with oblong male connector and included wiring harness
• Threaded mounting with 18 mm thread size and 22 mm hex size
• Metal housing with robust ceramic sensor construction for OE-style durability
• Fits 2012-2016 Mercedes-Benz SLK55 AMG, Upstream Left
• Fits 2012-2013 Mercedes-Benz SLK350, Upstream

Product Details

Bosch 17303 is part of the Bosch Actual OE Oxygen Sensor line, which focuses on OE-proven sensor design for modern engine management systems. Bosch pioneered the wideband planar pump-cell oxygen sensor architecture used in current low-emission and fuel-control strategies, and this sensor follows that OE development path with fast light-off, optimized heater control, and stable signal response under changing load conditions. For Mercedes-Benz SLK55 AMG and Mercedes-Benz SLK350 owners, Bosch 17303 provides the detailed exhaust feedback needed for accurate fuel trim control and emissions monitoring.

This part cross-references 0085428518 for the same application.

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 hesitation caused by inaccurate mixture feedback
• Reduced fuel economy from poor fuel trim control
• Emissions test failures tied to sensor response or heater issues

Installation Notes

Install Bosch 17303 in the upstream position specified for the vehicle application. Confirm the connector shape, terminal count, thread size, and harness length before installation. Because this is a specific-fit sensor, match the vehicle year, model, and position exactly for Mercedes-Benz SLK55 AMG and SLK350 applications.

Quality Assurance

Bosch supplies this oxygen sensor as an OE-style replacement backed by more than five decades of OE development in engine management and emissions technology. The design reflects Bosch’s long-standing role in wideband sensor development and aftermarket OE replacement coverage.