Bosch 13548 Oxygen Sensor - Upstream

Bosch OE Oxygen Sensor for Volkswagen Passat

Bosch 13548 is a specific-fit, narrow-band heated oxygen sensor built for precise air-fuel-ratio feedback to the ECU. It supports stable closed-loop fuel control and emissions management on the 1995 Volkswagen Passat, including upstream applications listed below.

Key Features

• Actual OE Oxygen Sensor from Bosch Actual OE Oxygen Sensor line
• Narrow-band heated O2 sensor for fast warm-up and closed-loop response
• Specific fit with threaded mounting and 18 mm thread size
• 4-wire design with blade terminals and oblong connector
• Wiring harness included; harness length 32.1 in
• Metal housing with high-temperature-resistant construction
• Overall length 35.8 in; sealing surface to connector end 34.6 in
• Hex size 22 mm for service removal and installation

Detailed Description

Bosch 13548 is engineered as a standard replacement oxygen sensor for vehicles that rely on narrow-band switching-type feedback. Bosch uses advanced ceramic sensing elements, optimized heater control, and durable materials to maintain accurate lambda measurement under heat and vibration. For Volkswagen Passat owners, this Bosch oxygen sensor supports the upstream exhaust position where the ECU depends on fast, stable signal input for fuel trim control and emissions performance. This part cross-references Bosch-style OE application references for the same vehicle fitment.

Fits 1995 Volkswagen Passat, upstream, from chassis # 3A..S..202 677. Fits 1995 Volkswagen Passat, upstream, without California Emission System. Bosch 13548 is a direct-fit option for these Volkswagen Passat applications and is listed for the same upstream location.

What It Helps Address

• Check engine light related to oxygen sensor signal faults
• Rough idle or unstable air-fuel mixture control
• Delayed closed-loop operation after cold start
• Excessive fuel consumption caused by inaccurate sensor feedback
• Emissions test failures tied to upstream O2 sensor performance

Installation Notes and Tips

Confirm the upstream sensor location before installation and verify the 18 mm threaded bung size. Inspect the connector shape, wire count, and harness routing against the original sensor on the 1995 Volkswagen Passat. Use the 22 mm hex for removal, and make sure the sealing surface is clean before threading in the replacement sensor. Bosch 13548 should be matched to the exact emission configuration noted in the fitment data.

Quality Assurance

Bosch has more than five decades of OE oxygen sensor development and supplies aftermarket sensors built to OE-proven standards. The Bosch Actual OE Oxygen Sensor line is based on original equipment engineering principles, with a focus on accurate signal output, heater performance, and durability in demanding exhaust conditions.