Bosch 13250 Oxygen Sensor - Downstream or Upstream

Bosch OE Oxygen Sensor for Subaru

Bosch 13250 is a narrow-band heated oxygen sensor built for specific Subaru applications, including Subaru Forester, Subaru Impreza, and Subaru Legacy fitments. It provides precise air-fuel ratio feedback to the ECU for stable closed-loop control and emissions monitoring.

The Bosch Actual OE Oxygen Sensor line draws on Bosch’s long OE development history, including narrowband planar sensor designs that improve light-off speed, lambda accuracy, and closed-loop response. Bosch 13250 uses a threaded metal housing, a square female connector, and an included wiring harness for direct replacement service on the listed Subaru vehicles.

Key Features

• Actual OE Oxygen Sensor from Bosch
• Narrow-band heated oxygen sensor design
• Specific fit for listed Subaru applications
• 4-wire configuration with pin terminals
• Square female connector with included wiring harness
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing for high-temperature and vibration resistance
• Part number 13250 for catalog and service reference

Fitment Details

• Fits 1998 Subaru Forester, downstream.
• Fits 1998 Subaru Impreza, downstream.
• Fits 1993-1995 Subaru Impreza, upstream.
• Fits 1990-1994 Subaru Legacy, upstream.

What This Sensor Helps Address

• Faulty oxygen sensor readings that affect fuel trim control
• Check engine light concerns related to O2 sensor performance
• Rough idle or inconsistent combustion caused by inaccurate air-fuel feedback
• Emissions test failures tied to a worn narrow-band sensor
• Slow closed-loop response from an aging heated oxygen sensor

Installation Notes

Verify the connector shape, wire count, mounting style, and sensor position before installation. Bosch 13250 is a specific-fit replacement for the listed Subaru Forester, Subaru Impreza, and Subaru Legacy applications, so matching the upstream or downstream location is important for correct service.

Use the 18 mm hex size and threaded mounting point to remove and install the sensor carefully. Confirm the harness routing and connector engagement before clearing diagnostic codes and returning the vehicle to service.

Quality Assurance

Bosch backs this Actual OE Oxygen Sensor line with more than five decades of OE sensor development. The design uses advanced ceramic elements, controlled heater operation, and high-temperature-resistant materials to maintain consistent signal quality under demanding thermal and vibration conditions. This part cross-references Subaru OE numbers 22690AA090 and 22690AA150 for the same application.