Bosch 18004 Oxygen Sensor - Downstream Left

Bosch OE Oxygen Sensor for Nissan Frontier and Xterra

Bosch 18004 is a narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It is a specific-fit replacement for the downstream left position on 2004 Nissan Frontier and 2004 Nissan Xterra, with OE-style construction for stable closed-loop control.

Key Features

• Specific-fit Bosch Actual OE Oxygen Sensor, part number 18004
• Narrow-band heated O2 sensor for accurate lambda feedback
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• 4-wire design with blade terminals and square connector
• Wiring harness included; harness length measures 41.8 in
• Metal housing with high-temperature-resistant materials for demanding exhaust conditions
• Fits 2004 Nissan Frontier, downstream left
• Fits 2004 Nissan Xterra, downstream left

Detailed Description

Bosch 18004 is part of Bosch’s Actual OE Oxygen Sensor line, which draws on decades of original-equipment development. Bosch uses advanced ceramic sensing elements, controlled heater operation, and durable materials to deliver fast sensor response and consistent readings under heat and vibration. For drivers searching for a Bosch 18004 oxygen sensor for 2004 Nissan Frontier downstream left or a Bosch 18004 oxygen sensor for 2004 Nissan Xterra downstream left, this replacement is built to match the vehicle’s OE-style sensor layout and electrical connection requirements.

This part cross-references 226A1EK800 for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Unstable air-fuel ratio feedback to the ECU
• Delayed closed-loop operation after startup
• Reduced emissions control efficiency
• Rough combustion control caused by an aging downstream sensor

Installation Notes and Tips

Confirm the downstream left location before ordering, since this is a specific-fit sensor for the listed Nissan applications. The threaded 18 mm design installs into the exhaust bung, and the 4-wire square connector should match the factory harness layout on the vehicle. Inspect the connector, wiring route, and exhaust threads before installation to ensure a clean electrical and mechanical connection.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE sensor development. The Actual OE Oxygen Sensor line is engineered to deliver OE-proven performance, accurate signal output, and durable operation in high-temperature exhaust environments.