Bosch 13108 Oxygen Sensor - Upstream

Bosch Actual OE Oxygen Sensor 13108

Bosch 13108 is an Actual OE Oxygen Sensor built for precise air-fuel-ratio feedback to the ECU. It is a narrow-band heated sensor with a specific fit, making it a direct replacement for select BMW upstream applications.

Key Features

• Actual OE Oxygen Sensor from Bosch
• Narrow-band heated oxygen sensor for closed-loop fuel control
• Specific fit with threaded mounting
• 4-wire design with round female connector
• Wiring harness included for the listed application
• 18 mm thread size and 22 mm hex size
• Metal housing with high-temperature-resistant construction

Product Line Details

Bosch Actual OE Oxygen Sensor products are based on Bosch’s long OE development history in oxygen sensing technology. This line uses ceramic sensing elements and controlled heater operation to support faster sensor warm-up, stable lambda feedback, and consistent performance under heat and vibration. Bosch 13108 follows that OE-focused approach for BMW upstream sensor replacement.

Detailed Description

This Bosch oxygen sensor is engineered to monitor exhaust oxygen content and send accurate switching signals to the engine control unit. That feedback helps the ECU maintain stable combustion control and emissions performance across changing operating conditions. For BMW owners searching for a Bosch 13108 oxygen sensor, this part is a direct-fit replacement for select upstream locations on 1987-1995 BMW 318i, 318is, 318ti, 325i, 325is, 525i, 525iT, 530i, 540i, 740i, 740iL, 750iL, 840Ci, 850Ci, 850CSi, 850i, and M3 applications. This part cross-references Bosch 13108 for the same application.

What It Helps Address

• Rich or lean fuel mixture readings from a worn upstream sensor
• Delayed closed-loop operation after cold start
• Check engine light concerns related to oxygen sensor performance
• Rough idle or unstable fuel control caused by inaccurate lambda feedback
• Emissions test failures tied to degraded sensor response

Installation Notes and Tips

Verify the connector shape, wire count, and threaded mounting style before installation. This sensor is an upstream, narrow-band heated unit with a 4-pin round female connector and 18 mm thread size. Use the vehicle’s exact year, model, and wire-length requirement to confirm the correct BMW application, especially on 740i, 740iL, 530i, and 540i listings with notes that vary by build date or harness length.

Quality Assurance

Bosch supplies oxygen sensors with OE development experience and materials selected for thermal and vibration resistance. Bosch 13108 is built to OE-style standards for accurate signal output and durable service in demanding exhaust environments.