Bosch 17020 Oxygen Sensor - Upstream or Upstream Left

Bosch Wideband OE Oxygen Sensor

Bosch 17020 is an Actual OE wideband air-fuel oxygen sensor built for precise mixture feedback and stable engine management. It delivers continuous lambda measurement for the ECU, helping maintain accurate fuel control on applications such as the Mercedes-Benz E320 and Mercedes-Benz CLK63 AMG.

The Bosch Actual OE Oxygen Sensor line reflects Bosch’s long OE development history and focuses on direct-fit replacement sensors with OE-proven construction. Part number 17020 uses a heated wide-band design with a 5-wire harness, 6 terminals, threaded mounting, and an included wiring harness for a specific-fit installation.

Key Features

• Wide-band oxygen sensor for continuous air-fuel ratio measurement
• Heated design for faster sensor activity after startup
• Specific-fit replacement for direct application matching
• 47 in wiring harness length with included harness
• Oblong male connector with blade terminals
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Robust metal housing for underhood durability

Detailed Description

Bosch 17020 is a wideband O2 sensor engineered for precise feedback across the full lambda range, giving the engine control unit more detailed data than a traditional switching sensor. That level of signal accuracy supports cleaner combustion control, steadier drivability, and consistent emissions performance under changing load and temperature conditions. This part number 17020 is a direct replacement choice for 2005-2006 Mercedes-Benz E320, upstream, and 2007-2009 Mercedes-Benz CLK63 AMG, upstream left.

As part of Bosch’s Actual OE Oxygen Sensor line, this sensor uses the same type of planar wideband architecture Bosch introduced for modern engine management systems. The result is a replacement sensor built around OE-style fitment, fast light-off behavior, and reliable heater control for demanding operating conditions.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings at the ECU
• Rough idle or inconsistent throttle response from faulty sensor feedback
• Reduced fuel economy caused by inaccurate mixture control
• Emissions test failures tied to upstream sensor issues

Installation Notes and Tips

Verify the connector shape, terminal count, thread size, and sensor position before installation. Bosch 17020 is a specific-fit, upstream wideband sensor for the listed Mercedes-Benz applications, so matching the original connector and harness routing is important. Use proper oxygen sensor service tools and confirm the exhaust threads are clean before threading the sensor into place.

Fits 2005-2006 Mercedes-Benz E320, upstream. Fits 2007-2009 Mercedes-Benz CLK63 AMG, upstream left. This part cross-references Mercedes-Benz 0035427218 for the same application.

Quality Assurance

Bosch backs this sensor with more than five decades of OE development in engine management and emissions technology. Part number 17020 is built to OE-style standards for accurate signal output, dependable heater operation, and long-term service in modern wideband applications.