Bosch 13666 Oxygen Sensor - Upstream Right

Bosch 13666 Oxygen Sensor for Infiniti Q45

Bosch 13666 is a narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It supports stable combustion control and emissions management for the 1998-2001 Infiniti Q45, upstream right position.

As part of Bosch Actual OE Oxygen Sensor line, this sensor reflects Bosch’s OE development in switching-type O2 sensing, including faster light-off, improved lambda accuracy, and quicker closed-loop response. Bosch 13666 uses durable ceramic and high-temperature materials to maintain consistent signal quality under heat and vibration.

• Fits 1998-2001 Infiniti Q45, upstream right
• Narrow-band heated oxygen sensor for closed-loop fuel control
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Specific-fit replacement for direct application matching
• Round connector with 4 terminal quantity and 3-wire harness design
• Steel finish and metal housing for underbody durability

How Bosch Actual OE Sensors Perform

The Bosch Actual OE Oxygen Sensor line is built around OE-proven sensing technology used to measure exhaust oxygen content and relay accurate feedback to the engine control unit. For the Infiniti Q45 upstream right application, Bosch 13666 helps maintain proper air-fuel correction during warm-up, cruise, and load changes. This part number, 13666, is a direct replacement choice for drivers servicing emissions-related sensor faults on the Q45.

This part cross-references 226906P603 for the same application.

Common Issues This Sensor Addresses

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Rough idle or unstable fuel control after sensor aging
• Slow closed-loop response during warm-up or driving transitions
• Emissions test failure caused by a degraded upstream sensor

Installation Notes and Tips

Confirm the upstream right location before installation and verify connector style, thread size, and harness routing against the removed sensor. Use proper oxygen sensor service tools to avoid damaging the threaded bung, and inspect the exhaust threads for corrosion or contamination before threading in Bosch 13666. After installation, clear diagnostic trouble codes and verify fuel trim and sensor switching behavior.

Quality Assurance

Bosch has more than five decades of OE oxygen sensor development behind this Actual OE replacement line. Bosch 13666 is engineered to deliver OE-level sensing accuracy and durable operation for the 1998-2001 Infiniti Q45, upstream right.