Bosch 16125 Oxygen Sensor - Downstream

Bosch OE Oxygen Sensor for Mercedes-Benz

Bosch 16125 is an Actual OE Oxygen Sensor built as a narrow-band heated replacement for precise air-fuel ratio feedback to the ECU. It is a specific-fit sensor with a 4-wire harness, round female connector, and threaded mounting for direct replacement service on select Mercedes-Benz applications.

The Bosch Actual OE Oxygen Sensor line reflects Bosch’s long OE development history in oxygen sensing, with designs focused on stable closed-loop control, faster sensor response, and consistent operation under heat and vibration. For drivers servicing a Mercedes-Benz SLK230, CL600, or S600, Bosch 16125 provides an OE-style solution for downstream emissions monitoring.

Key Features

• Part number 16125
• Actual OE Oxygen Sensor from Bosch
• Narrow-band heated oxygen sensor design
• Specific fit with threaded mounting
• 4-wire harness with round female connector
• 18 mm thread size and 22 mm hex size
• Steel finish with metal housing
• Wiring harness included

Detailed Description

Bosch 16125 uses a switching-type narrow-band sensor element to measure exhaust oxygen content and send accurate feedback to the engine control unit. That signal helps maintain stable combustion control and emissions performance during normal driving and warm-up operation. The heated design supports quicker closed-loop operation, while the OE-focused construction uses high-temperature-resistant materials for durability in demanding exhaust conditions.

This Bosch Actual OE Oxygen Sensor is a direct replacement for downstream service on 2001-2004 Mercedes-Benz SLK230, 2001-2002 Mercedes-Benz CL600, and 2001-2002 Mercedes-Benz S600. If you are searching for a downstream oxygen sensor for Mercedes-Benz SLK230, CL600, or S600, Bosch 16125 is the correct OE-style service part for those listed applications. This part cross-references Mercedes-Benz 0015403817 for the same application.

What It Helps Address

• Faulty oxygen sensor signal causing incorrect fuel trim
• Check engine light related to downstream O2 sensor performance
• Rough idle or inconsistent combustion control from aging sensor response
• Emissions test failures tied to oxygen sensor degradation
• Slow closed-loop transition after startup

Installation Notes and Tips

Verify the connector style, wire count, and downstream location before installation. The sensor uses an 18 mm thread and threaded mounting, so the exhaust bung should be clean and undamaged before threading in the replacement. Confirm the harness routing matches the original layout and keep the lead away from hot exhaust surfaces and moving components.

Quality Assurance

Bosch supplies oxygen sensors with OE development experience and materials selected for thermal and vibration resistance. Bosch 16125 is part of the Bosch Actual OE Oxygen Sensor line, built to OE-proven specifications for the listed Mercedes-Benz applications.