Bosch 16984 Oxygen Sensor - Downstream or Downstream Left

Bosch Actual OE Oxygen Sensor for Volkswagen and Audi

Bosch Part Number 16984 is a specific-fit, narrow-band heated oxygen sensor built for downstream applications on select Volkswagen and Audi vehicles. It delivers air-fuel-ratio feedback to the ECU for stable closed-loop control, accurate lambda monitoring, and lower emissions.

As part of Bosch’s Actual OE Oxygen Sensor line, this sensor reflects Bosch’s long-running OE development in switching-type O2 sensing, with a focus on fast light-off, accurate signal response, and durable operation in high-heat, high-vibration exhaust environments.

• Specific-fit oxygen sensor for direct application matching
• Narrow-band heated sensor design for downstream exhaust monitoring
• 4-wire layout with blade terminals and oblong connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included for cleaner replacement routing
• Metal housing and high-temperature-resistant construction
• Bosch 16984 for OE-style replacement performance

How Bosch 16984 Works

This Bosch oxygen sensor measures exhaust oxygen content and sends a switching signal to the ECU so the engine can maintain the correct air-fuel ratio. That matters on vehicles such as the Volkswagen Passat, Volkswagen CC, Volkswagen Touareg, and Audi Q7, where downstream sensor feedback is used to monitor catalyst efficiency and overall emissions performance. Bosch 16984 is also listed for Audi A6 Quattro downstream applications and select Passat CC and Passat downstream-left positions.

Bosch’s Actual OE Oxygen Sensor line is based on decades of original-equipment development. The design uses advanced ceramic sensing elements, controlled heater operation, and materials selected to withstand thermal cycling and vibration, helping maintain consistent signal quality over time.

This part cross-references 1K0998262C for the same application.

Common Issues This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Slow or unstable downstream sensor response
• Incorrect catalyst efficiency readings
• Emissions test failure tied to O2 sensor faults
• Rough closed-loop fuel control caused by a worn sensor

Installation Notes and Fitment

Fits 2012-2018 Volkswagen Passat, downstream. Fits 2009-2017 Volkswagen CC, downstream left. Fits 2007-2010 Audi Q7, downstream. Fits 2008-2010 Volkswagen Passat, downstream left. Fits 2009-2010 Volkswagen Passat CC, downstream left. Fits 2007-2009 Volkswagen Touareg, downstream. Fits 2006-2007 Volkswagen Passat, downstream left. Fits 2005-2006 Audi A6 Quattro, downstream, cylinder(s) 5 to 8. Fits 2005-2006 Audi A6 Quattro, downstream, cylinder(s) 1 to 4.

Confirm the connector style, thread size, and sensor position before installation. Use the existing harness routing and mounting location as a reference, and verify the downstream or downstream-left placement against the vehicle’s original sensor.

Quality Assurance

Bosch supplies this oxygen sensor as an OE-proven replacement backed by more than five decades of oxygen-sensor development. The Actual OE Oxygen Sensor line is built to meet the demands of modern emissions systems while maintaining the signal accuracy and durability expected from Bosch aftermarket components.