Bosch 15170 Oxygen Sensor - Downstream

Bosch Validated Oxygen Sensor for Subaru Downstream Applications

Bosch Validated Oxygen Sensor 15170 is a specific-fit, narrow-band heated O2 sensor built for downstream air-fuel monitoring. It delivers precise feedback to the ECU so the engine can maintain stable combustion control and emissions performance across changing operating conditions.

Compatible With 2006-2012 Subaru Legacy, 2006-2012 Subaru Outback, 2006-2011 Subaru Impreza, 2006-2010 Subaru Forester, and 2006 Saab 9-2X in downstream positions. This Bosch Validated Oxygen Sensor 15170 is a direct replacement choice for vehicles that need OE-style sensor response and reliable closed-loop operation.

Key Features

• Specific-fit oxygen sensor for downstream placement
• Narrow-band heated sensor design for faster light-off and quicker closed-loop operation
• 4-wire harness with rectangular male connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included with 18.3 in harness length
• Standard replacement grade for emission control service
• Metal housing built for high-temperature and vibration exposure

Product Details

Bosch Validated Oxygen Sensor 15170 uses Bosch’s long-running OE sensor development to provide accurate lambda feedback in a durable aftermarket replacement. The heated narrow-band design helps the sensor reach operating temperature quickly, while the ceramic sensing element and heater control support consistent signal output under demanding thermal conditions. For Subaru Legacy, Outback, Impreza, and Forester downstream service, this sensor is built to restore proper exhaust monitoring and support emissions system function.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What This Sensor Helps Address

• Check engine light related to downstream oxygen sensor performance
• Slow or inaccurate oxygen sensor response
• Unstable air-fuel ratio feedback to the ECU
• Emissions test failures tied to sensor degradation
• Rough combustion control caused by aging exhaust sensors

Installation Notes

Install in the downstream sensor location only. Verify the 18 mm thread size, 22 mm hex size, 4-wire connector layout, and rectangular male plug before installation. Because this is a threaded sensor with an included harness, route the lead away from exhaust heat and inspect the connector and wiring path for damage before final connection.

Quality Assurance

Bosch has decades of OE oxygen sensor development behind this Validated Oxygen Sensor line, and part 15170 reflects that experience in a standard replacement format for Subaru and Saab applications.