Bosch 13115 Oxygen Sensor - Upstream

Bosch Oxygen Sensor for Ford and Mercury

Bosch 13115 is a narrow-band heated oxygen sensor built for specific upstream applications on select Ford and Mercury vehicles. It provides the ECU with air-fuel-ratio feedback needed for stable combustion control and emissions management, with a square connector, 4-wire design, and included wiring harness for direct replacement service.

Key Features

• Bosch Engineered Oxygen Sensor, part number 13115
• Specific fit replacement for upstream locations
• Narrow-band heated oxygen sensor for closed-loop fuel control
• 4-wire design with blade terminals and square male connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing with high-temperature-resistant construction
• Wiring harness included; harness length measures 22.7 in

Product Details

Bosch 13115 uses a switching-type narrow-band sensing element to report oxygen content in the exhaust stream so the engine control unit can adjust fueling accurately. Bosch’s oxygen sensor development traces back to its original OE work in the 1970s, and this sensor line continues that focus with ceramic sensing elements, controlled heater operation, and materials selected for heat and vibration resistance. It is a direct-fit upstream sensor for 1995-1999 Ford Contour, 1995-1999 Mercury Mystique, and 1999 Mercury Cougar applications. This part cross-references Bosch 13115 for the same application.

Common Issues This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Rich or lean fuel trim readings from a worn upstream sensor
• Slow closed-loop response during warm-up and normal driving
• Reduced emissions control from an aging narrow-band sensor
• Rough idle or drivability concerns tied to inaccurate exhaust feedback

Installation Notes and Tips

Install Bosch 13115 in the upstream sensor location only when the vehicle callout matches the application. Confirm the 18 mm thread size, 22 mm hex size, 4-wire connector layout, and square connector shape before installation. Inspect the exhaust bung threads and wiring routing, and verify the harness length provides proper reach without strain. For 1999 Mercury Cougar, use the listed upstream application notes, including the 04/1999 cutoff where applicable.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development experience. The Bosch Engineered Oxygen Sensor line is built to OE-style standards for accurate signal delivery, stable heater performance, and durable operation in demanding thermal conditions.