Bosch 16123 Oxygen Sensor - Downstream, Downstream Left or Upstream

Bosch Actual OE Oxygen Sensor 16123

Bosch 16123 is a specific-fit, narrow-band heated oxygen sensor for select Chrysler and Mercedes-Benz applications. It provides the ECU with accurate air-fuel-ratio feedback for stable closed-loop operation and emissions control.

Key Features

• Actual OE Oxygen Sensor from Bosch Actual OE Oxygen Sensor line
• Narrow-band heated O2 sensor with threaded mounting
• 4-wire design with round female connector and pin terminals
• Specific fit replacement with wiring harness included
• Metal housing with high-temperature-resistant construction
• 22 mm hex size and 18 mm thread diameter

Product Details

Bosch 16123 uses a switching-type narrow-band design to measure exhaust oxygen content and send precise feedback to the engine control unit. Bosch developed this sensor family from its original OE oxygen sensor technology and later planar narrowband designs, focusing on faster light-off, improved lambda accuracy, and quicker closed-loop response. For drivers servicing a Mercedes-Benz ML320, ML350, ML430, ML500, SLK230, or a Chrysler Crossfire, Bosch 16123 supports accurate fuel control in the downstream or upstream location specified by the vehicle application. This part cross-references 5099817AA and 0015403717 for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Rich or lean air-fuel mixture readings
• Slow closed-loop fuel control response
• Emissions test failures tied to sensor output
• Rough combustion control caused by inaccurate exhaust feedback

Installation Notes

Verify the sensor position before installation: Fits 2004-2008 Chrysler Crossfire, Downstream Left; Fits 2003-2005 Mercedes-Benz ML350, Downstream; Fits 2002-2005 Mercedes-Benz ML500, Downstream; Fits 2001-2004 Mercedes-Benz SLK230, Upstream; Fits 2001-2003 Mercedes-Benz ML320, Downstream; Fits 2001 Mercedes-Benz ML430, Downstream. Confirm connector shape, wire count, thread size, and harness length against the original sensor before replacement. Use the correct oxygen sensor socket and follow the vehicle service procedure for removal and torque.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development and aftermarket supply experience. The design reflects Bosch OE engineering standards for durability, thermal resistance, and measurement accuracy across demanding operating conditions.