Walker 250-21000 Oxygen Sensor - Upstream

Walker OE Oxygen Sensor 250-21000

Walker Products OE 250-21000 is a universal, threaded oxygen sensor built for specific upstream applications where accurate exhaust feedback is needed by the ECU. It is designed for vehicles such as Chevrolet Chevy, Nissan Sentra, Nissan Pickup, and Mercedes-Benz 380-series models listed below.

Key Features

• Walker Products OE line replacement oxygen sensor
• Part number 250-21000 for upstream applications
• Non-heated sensor design
• Universal fit with threaded mounting
• 18.0 mm thread diameter
• 5.83 in. wiring harness length
• 20-gauge wire with 1-wire configuration
• Overall length: 9.37 in.

Product Details

Walker Products Engine Management and Oxygen/Air-Fuel sensors are engineered as OE-style replacements for specific vehicle applications and fitment positions. This Walker Products OE sensor is intended for upstream placement and provides the diagnostic feedback the engine control unit relies on for fuel control and emissions monitoring. The 250-21000 is a practical choice for older import and domestic applications that use a non-heated, threaded oxygen sensor design.

Compatible With 1996-2003 Chevrolet Chevy, upstream; 2000 Nissan Sentra, upstream; 1985-1995 Nissan Pickup, upstream; 1991-1994 Chevrolet S10 Blazer, upstream; and select Mercedes-Benz 380SE, 380SL, 500SEC, 500SEL, 380SEL, and 380SLC upstream applications. This part cross-references no listed aftermarket part numbers in the provided data.

Common Symptoms Addressed

• Check engine light or malfunction indicator light related to oxygen sensor performance
• Poor engine operation caused by incorrect exhaust feedback
• Increased fuel consumption from inaccurate air-fuel control
• Higher exhaust emissions from a failing upstream sensor
• Stored ECU fault codes tied to the affected sensor circuit

Installation Notes

Install in the upstream position only for the listed applications. Verify the sensor connector, wiring harness, and surrounding exhaust components for physical damage before installation, since damaged wiring can shorten sensor life and affect signal quality. Confirm thread size and mounting style match the vehicle before service. For Mercedes-Benz applications, follow the listed upstream installation guidance for proper performance.

Quality Assurance

Walker Products is an ISO 9001/TS 16949 certified automotive manufacturer with a long history in engine management and fuel system components. The Walker Products OE line is built around application-specific fitment and ECU feedback requirements for the listed vehicles.