Bosch 13591 Oxygen Sensor - Downstream

Bosch Actual OE Oxygen Sensor 13591

Bosch 13591 is a narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It is a specific-fit replacement for downstream applications on select Nissan Quest and Mercury Villager models, helping maintain stable combustion control and lower emissions.

Key Features

• Actual OE Oxygen Sensor from Bosch Actual OE Oxygen Sensor line
• Narrow-band heated O2 sensor for closed-loop fuel control
• Specific fit with threaded mounting and square 4-pin connector
• 4-wire design with included wiring harness
• Metal housing with high-temperature-resistant construction
• 22 mm hex size and 18 mm thread diameter
• Wiring harness length: 51.6 in; sealing surface to connector end: 50.4 in

Detailed Description

Bosch 13591 uses Bosch OE development experience to deliver accurate oxygen sensing for downstream emissions monitoring and fuel-trim correction. The sensor’s heated narrow-band design supports quicker closed-loop operation after startup, while the ceramic sensing element and heater control help maintain consistent signal output under thermal and vibration stress. This Bosch oxygen sensor is a direct replacement choice for 1996-1998 Mercury Villager downstream and 1996-1997 Nissan Quest downstream applications. If you are replacing a Bosch 13591 oxygen sensor on a Nissan Quest or Mercury Villager, this part matches the specified fitment and connector style.

This part cross-references 226A01B014 for the same application.

What It Helps Address

• Check engine light related to downstream oxygen sensor performance
• Unstable air-fuel ratio feedback to the ECU
• Slow closed-loop response after engine warm-up
• Emissions test failures tied to sensor signal degradation
• Rough fuel control caused by aging narrow-band sensor output

Installation Notes and Tips

Verify downstream location, connector shape, wire count, and thread size before installation. Use the threaded mounting point and confirm the 18 mm thread diameter and 22 mm hex size match the original sensor. Route the included harness away from exhaust heat and moving components, and inspect the connector for corrosion before plugging in the replacement. For Nissan Quest and Mercury Villager applications, confirm the downstream position and harness length before final fitment.

Quality Assurance

Bosch has more than five decades of OE oxygen sensor development behind this design. The Bosch 13591 is built to OE-style standards for accurate signal response, durable heater performance, and long-term service in demanding exhaust environments.