Bosch 18138 Oxygen Sensor - Downstream

Bosch Validated Oxygen Sensor 18138

Bosch Validated Oxygen Sensor 18138 is a narrow-band heated downstream O2 sensor built for precise air-fuel-ratio feedback to the ECU. It supports stable combustion control and emissions management for select Ford and Lincoln applications, including Fusion, MKZ, C-Max, Escape, Transit Connect, and SSV Plug-In Hybrid models.

Key Features

• Specific-fit downstream oxygen sensor for confirmed vehicle applications
• Narrow-band heated design for faster closed-loop operation
• Square connector with 4-wire harness and pin terminals
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing and high-temperature-resistant construction
• Wiring harness included for direct replacement use
• Bosch Validated Oxygen Sensor line reflects Bosch OE development experience

Product Details

Bosch part number 18138 uses a switching-type narrow-band design to measure exhaust oxygen content and send accurate feedback to the engine control unit. Bosch developed this sensor family from its early oxygen sensor work and later planar narrowband designs, focusing on quicker light-off, improved lambda accuracy, and faster closed-loop response. For drivers servicing a Ford Fusion downstream oxygen sensor, Lincoln MKZ downstream O2 sensor, or Ford Escape downstream oxygen sensor, this replacement follows the OE-style layout and electrical configuration needed for proper signal delivery.

This part cross-references Bosch Validated Oxygen Sensor applications for the same vehicle coverage. The Bosch Validated Oxygen Sensor line is backed by more than five decades of OE development and uses ceramic sensing elements, optimized heater control, and durable materials for consistent operation under heat and vibration.

What It Helps Address

• Check engine light related to downstream oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Slow sensor response during closed-loop operation
• Emissions test failures tied to oxygen sensor faults
• Rough combustion control caused by inaccurate exhaust readings

Installation Notes

• Compatible With 2013-2020 Ford Fusion, downstream
• Compatible With 2019-2020 Ford SSV Plug-In Hybrid, downstream
• Compatible With 2013-2020 Lincoln MKZ, downstream
• Compatible With 2013-2018 Ford C-Max, downstream
• Compatible With 2013-2016 Ford Escape, downstream
• Compatible With 2014-2016 Ford Transit Connect, downstream

Verify connector shape, thread size, and downstream location before installation. The threaded sensor body and included harness support direct replacement on the listed applications, and proper routing helps protect the wiring from exhaust heat and vibration.

Quality Assurance

Bosch manufactures this oxygen sensor using OE-focused engineering practices and validated materials for long-term signal accuracy and thermal durability. Part number 18138 is built to Bosch standards for the listed Ford and Lincoln applications.