Walker 250-21020 Oxygen Sensor - Upstream

Walker OE Oxygen Sensor for Upstream Applications

Walker Products OE oxygen sensor Part Number 250-21020 is a specific-fit replacement for upstream emission control applications. It is engineered for vehicles that rely on accurate exhaust feedback to help the ECU manage fuel delivery and monitor sensor performance.

• Specific-fit oxygen sensor for upstream placement
• Non-heated sensor design
• Threaded mounting type with 18.0 mm thread diameter
• Radiused polygon male connector
• 19.41 in. wiring harness length
• 20-gauge wire with 1-wire configuration
• Overall length: 22.95 in.

Walker Products OE Line Details

Walker Products OE focuses on original-equipment-style engine management and oxygen/air-fuel sensors built for defined vehicle applications and sensor positions. Part Number 250-21020 follows that approach with application-specific fitment for upstream use, helping maintain the diagnostic feedback expected by the ECU on supported vehicles.

This oxygen sensor is listed for 1990-1992 Ford Probe, upstream; 1990-1992 Mazda 626, upstream; 1990-1992 Mazda MX-6, upstream; and 1993-1995 Mazda RX-7, upstream. It is a direct-fit choice for drivers searching for a 1990-1992 Ford Probe upstream oxygen sensor, a 1990-1992 Mazda 626 Bank 1 Sensor 1 replacement, or a 1993-1995 Mazda RX-7 front oxygen sensor. Part Number 250-21020 is also referenced as Walker Products OE 250-21020 for these applications.

What This Oxygen Sensor Helps Address

• Check engine 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
• Fault codes stored in the ECU for sensor-related issues

Installation Notes and Tips

Confirm the vehicle uses an upstream, specific-fit oxygen sensor before installation. Inspect the sensor wiring harness and connector for damage, since physical wear can shorten service life and affect signal quality. Verify thread size, connector shape, and harness length against the original part to ensure proper fit on the Mazda RX-7, Mazda 626, Mazda MX-6, or Ford Probe application.

Quality Assurance

Walker Products is an Automotive ISO9001/TS 16949 certified company with a long history in engine management components. Part Number 250-21020 is built as an OE-style replacement for defined applications and sensor positions.