NTK 25503 Oxygen Sensor - Upstream

Direct Fit Oxygen Sensor

NTK Direct Fit Oxygen Sensor 25503 is a specific-fit emission control sensor for compatible Porsche 944 applications. It uses a threaded mounting design and a non-heated, single-wire configuration for direct replacement service.

• Specific-fit oxygen sensor for emission control service
• Non-heated design with one-wire construction
• Threaded mounting for secure installation
• 34-inch wiring harness length
• 18 mm thread diameter

Fitment Details

Fits 1983-1985 Porsche 944, upstream. This part cross-references Monroe Shocks & Struts (e.g., 213-513, 213-2863) for the same application.

NTK is part of the NGK family and focuses on oxygen sensor coverage for import and domestic vehicles. As a major original equipment oxygen sensor supplier, NTK builds this sensor with manufacturing controls intended to deliver fit, form, and function aligned with OE expectations. The 25503 is a direct-fit replacement for Porsche 944 emission control service, and the 25503 part number is useful when matching the correct sensor for the listed application.

What It Helps Address

• Faulty oxygen sensor readings
• Emission control warning conditions
• Rough fuel mixture correction issues
• Sensor replacement during exhaust service

Installation Notes

Verify the threaded mounting style, harness length, and non-heated configuration before installation. Confirm the upstream location and compare the connector and thread specifications to the original sensor on the vehicle. Use the 25503 part number to confirm application details before ordering.

Quality Assurance

NTK states that these oxygen sensors are extensively tested during manufacturing to meet or exceed OE specifications. The 25503 is built under NTK's OE-focused sensor program for application-specific replacement service.