Bosch 16531 Oxygen Sensor - Downstream

Bosch Actual OE Oxygen Sensor 16531

Bosch 16531 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 downstream applications on select Audi models, including Audi A8 Quattro, RS7, S6, S7, and S8.

As part of Bosch’s Actual OE Oxygen Sensor line, this sensor reflects Bosch’s long OE development history in oxygen sensing technology. The design uses a threaded metal housing, a 4-wire harness, and a male oblong connector to match the original equipment style on the listed vehicles.

Key Features

• Specific-fit downstream oxygen sensor for select Audi applications
• Narrow-band heated sensor type for closed-loop fuel control
• 4-wire design with included wiring harness
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing built for high-temperature and vibration exposure
• OE-style connector layout for direct replacement use

Product Details

Bosch 16531 is engineered as a standard replacement oxygen sensor for downstream locations on 2013-2018 Audi A8 Quattro, 2014-2018 Audi RS7, 2013-2018 Audi S6, 2013-2018 Audi S7, and 2013-2018 Audi S8. It measures exhaust oxygen content so the ECU can adjust fueling accurately across changing operating conditions. Bosch’s narrow-band planar sensor approach is known for quicker light-off and faster closed-loop response than older sensor designs, while the ceramic sensing element and heater control help maintain consistent signal quality under heat and vibration.

This part cross-references Bosch OE application 4H0906262M for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings at the ECU
• Rough idle or inconsistent fuel control from a failing downstream sensor
• Emissions test failures caused by degraded sensor response
• Slow closed-loop operation after sensor aging or contamination

Installation Notes and Tips

Verify downstream placement before installation and confirm the connector, thread size, and harness length match the original sensor. The sensor uses a threaded mount with an 18 mm thread diameter and a 22 mm hex, so proper removal and installation tools are recommended. Inspect the exhaust bung and wiring routing before fitting the new sensor to avoid thread damage or harness strain.

Quality Assurance

Bosch supplies this Actual OE Oxygen Sensor using OE-proven development and materials selected for durability in demanding exhaust environments. The part is built to deliver the same type of signal accuracy and thermal resilience expected from Bosch’s original equipment sensor programs.