Walker 250-21028 Oxygen Sensor - Upstream

OE Oxygen Sensor for Saturn and GM Applications

Walker Products OE 250-21028 is a specific-fit oxygen sensor engineered as an original equipment replacement for select Saturn, Chevrolet, GMC, Isuzu, Oldsmobile, and Pontiac applications. It is built for upstream placement and provides the ECU with the feedback needed to monitor air-fuel control and emissions performance.

Walker Products OE focuses on application-specific engine management sensors, and this part number is matched to the required fitment position and connector style for the listed vehicles. For shoppers searching for an upstream oxygen sensor for a 1995-2002 Saturn SC1 or a 1999-2000 Chevrolet S10, 250-21028 is the OE-style replacement to review.

Key Features

• Specific-fit upstream oxygen sensor for targeted vehicle applications
• Non-heated sensor design
• Threaded mounting with 18.0 mm thread diameter
• Radiused polygon female connector
• 13.31 in. wiring harness length with 20-gauge wire
• Overall length: 16.85 in.
• Walker Products OE line for application-matched engine management replacement parts

Detailed Description

Walker Products OE 250-21028 is an oxygen sensor designed for upstream installation where the engine control unit relies on accurate exhaust feedback to manage fuel delivery and emissions. The sensor is application-specific, so the connector, harness length, mounting style, and sensor configuration are matched to the listed vehicles rather than offered as a universal part. This makes it a practical choice for drivers replacing a failed upstream oxygen sensor on Saturn SC1, SC2, SL, SL1, SL2, SW1, and SW2 models, as well as select Chevrolet S10, GMC Sonoma, Isuzu Hombre, Chevrolet Cavalier, Chevrolet Malibu, Oldsmobile Alero, Pontiac Grand Am, and Pontiac Sunfire applications.

Walker Products OE parts are developed as OE replacement components for engine management systems, with fitment and diagnostic feedback aligned to the vehicle’s ECU requirements. Part number 250-21028 is a threaded, non-heated sensor with a female connector and a radiused polygon connector shape, making it important to verify the original sensor configuration before ordering. This part cross-references Standard Motor Products (e.g., SG180, SG181) for the same application.

What It Helps Address

• Check engine light related to upstream oxygen sensor performance
• Poor fuel economy caused by incorrect air-fuel feedback
• Rough running or hesitation from inaccurate exhaust readings
• Higher exhaust emissions from a failing sensor
• Stored ECU fault codes tied to the affected sensor circuit

Installation Notes and Tips

Confirm the vehicle’s original sensor position before ordering, since this part is for upstream applications only. Inspect the sensor wiring harness and connector for heat damage, corrosion, or broken terminals before installation, because damaged wiring can shorten sensor life and affect ECU readings. Verify thread size, connector shape, and harness length against the removed part to ensure proper fitment on the listed Saturn, Chevrolet, GMC, Isuzu, Oldsmobile, and Pontiac models.

Quality Assurance

Walker Products has supplied engine management and fuel system components since 1946 and manufactures OE-style replacement sensors under ISO 9001/TS 16949 quality systems. The Walker Products OE line is built around application-specific fitment and diagnostic performance for modern engine control systems.