Bosch 17444 Oxygen Sensor - Upstream

Bosch Wideband OE Oxygen Sensor

Bosch 17444 is an Actual OE Oxygen Sensor built as a wideband air/fuel sensor for precise mixture feedback to the ECU. It is a specific-fit, heated replacement for select applications and is listed for 2008-2015 Smart Fortwo upstream positions.

The Bosch Actual OE Oxygen Sensor line focuses on OE-style fit, fast response, and stable signal output across the full lambda range. Bosch 17444 uses a wide-band design with a 5-wire harness, 6 terminals, oblong male connector, and threaded 18 mm mounting for direct replacement service on the correct vehicle application.

• Wide-band A/F oxygen sensor for continuous air-fuel ratio measurement
• Heated sensor with optimized heater control for quicker operating readiness
• Specific-fit design for direct replacement service
• 5-wire harness with included wiring harness
• Threaded mounting, 18 mm thread diameter, 22 mm hex size
• Overall length: 14.2 in; sealing surface to connector end: 13 in
• Steel finish with metal housing for OE-style durability

Fitment Details

Fits 2008-2015 Smart Fortwo, upstream. This Bosch 17444 oxygen sensor is listed for the upstream position on the Smart Fortwo across the 2008, 2009, 2010, 2011, 2012, 2013, 2014, and 2015 model years.

This part cross-references Mercedes-Benz 0055429818 for the same application.

What This Sensor 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 feedback
• Reduced fuel economy caused by inaccurate exhaust oxygen measurement
• Higher emissions from delayed or unstable sensor response

Installation Notes

Verify the upstream location, connector shape, wire count, and 18 mm thread size before installation. Use the vehicle’s original routing and connector path, and confirm the sensor seats fully at the threaded mounting point. Because this is a specific-fit Bosch 17444 sensor, matching the application exactly is important for proper ECU feedback.

Quality Assurance

Bosch developed the first wideband A/F oxygen sensor and supplies OE-proven sensor technology to the aftermarket. Bosch 17444 reflects that OE development background with a wide-band ceramic sensor design, fast light-off characteristics, and durable construction for modern engine management systems.