Walker 250-21056 Oxygen Sensor - Upstream

Walker Products OE Oxygen Sensor 250-21056

Walker Products OE 250-21056 is a specific-fit oxygen sensor for older Toyota and Chevrolet applications that require an upstream, non-heated sensor with OE-style feedback to the ECU. It is built for direct replacement use on select Toyota MR2, Supra, Corolla, 4Runner, Pickup, Tercel, Van, Celica, Cressida, Land Cruiser, and Chevrolet Nova applications.

Key Features

• Specific-fit oxygen sensor for targeted vehicle applications
• Upstream sensor position for Bank 1 Sensor 1 and front sensor locations where listed
• Non-heated sensor design
• Flange mount construction
• Female connector with radiused polygon shape
• 17.44 in. wiring harness length and 20-gauge wire
• 18.0 mm thread diameter
• 20.98 in. overall length

Walker Products OE Line Details

Walker Products OE focuses on original-equipment-style replacement sensors engineered for application-specific fitment and ECU feedback requirements. The 250-21056 follows that approach for select Toyota and Chevrolet vehicles, making it a practical choice when replacing an upstream oxygen sensor on older fuel-injection and emissions-control systems.

Detailed Description

Walker Products Part Number 250-21056 is an upstream oxygen sensor designed for specific applications rather than universal use. It is listed for 1981-1992 vehicles across Toyota and Chevrolet platforms, including 1992 Toyota MR2 upstream, 1989-1992 Toyota Supra upstream, 1983-1989 Toyota Corolla upstream, 1985-1988 Toyota 4Runner upstream, 1985-1988 Toyota Pickup upstream, 1983-1988 Toyota Tercel upstream, 1981-1988 Toyota Cressida upstream, 1981-1986 Toyota Celica upstream, 1985-1988 Chevrolet Nova upstream, 1987 Toyota Van upstream, and 1985 Toyota Land Cruiser upstream. If you are searching for a Walker Products OE 250-21056 oxygen sensor for a Toyota MR2 upstream application or a Toyota Supra upstream oxygen sensor, this part is built around those exact fitment needs.

This sensor is intended to restore proper exhaust-gas feedback to the ECU on vehicles that rely on an upstream oxygen sensor for mixture control and emissions monitoring. The non-heated design, flange mount, and application-specific connector help support correct installation on the listed vehicles.

What It Helps Address

• Check engine light related to upstream oxygen sensor faults
• Poor engine performance caused by incorrect air-fuel feedback
• Increased fuel consumption from a failing sensor signal
• Higher exhaust emissions on affected Toyota and Chevrolet models
• Diagnostic trouble codes stored in the ECU for sensor-related issues

Installation Notes and Tips

Verify the vehicle’s year, engine configuration, and sensor position before ordering. This part is listed for upstream locations only, including Bank 1 Sensor 1 and front sensor applications where noted. Inspect the sensor wiring harness and connector for heat damage, corrosion, or physical wear before installation, since damaged wiring can shorten sensor life and affect readings. Confirm the flange mount and 18.0 mm thread diameter match the original sensor location.

Quality Assurance

Walker Products states that its engine management and oxygen sensor lines are developed as OE replacement parts and manufactured under Automotive ISO9001/TS 16949 quality systems. Part number 250-21056 is built to meet the application-specific feedback requirements expected by the ECU on the listed vehicles.