NTK 25640 Oxygen Sensor - Upstream

Direct-Fit Oxygen Sensor

This NTK oxygen sensor is a specific-fit, heated replacement built for emission control applications. It is engineered for direct installation and supports accurate exhaust monitoring on compatible vehicles.

• Heated oxygen sensor with a 4-wire design for stable signal performance.
• Threaded mounting with an 18 mm thread diameter.
• 34.75-inch wiring harness length for application-specific routing.
• NTK Direct Fit Oxygen Sensor line focuses on OE-style fit, form, and function.

Application Details

Fits 1995 Volkswagen Passat, upstream. This part number 25640 is listed for B1S1 applications from chassis 3A-S-202 677 and uses an OE-equivalent direct-fit design. For buyers searching for a 1995 Volkswagen Passat upstream oxygen sensor, part number 25640 matches the specified application.

Common Issues It May Address

• Faulty oxygen sensor readings that can affect fuel control.
• Check engine light concerns related to upstream exhaust monitoring.
• Rough idle or drivability issues caused by inaccurate air-fuel feedback.
• Emission test failures tied to a worn sensor.

Installation Notes

Verify the upstream location, chassis break, and OE-equivalent design before installation. Confirm the threaded mounting style, 18 mm thread diameter, and harness length against the original sensor. Use the vehicle service information for proper routing and connector matching on the Volkswagen Passat application.

Quality Assurance

NTK states that these oxygen sensors are extensively tested during manufacturing to meet or exceed OE specifications. The brand is part of the NGK family and is recognized for OE oxygen sensor manufacturing and application coverage. Part number 25640 is supported by NTK's direct-fit product line for import and domestic applications.