Walker 250-25175 Oxygen Sensor - Upstream

OE Base Wide-Band Oxygen Sensor

Walker OE Base Sensor 250-25175 is a specific-fit heated wide-band oxygen sensor built for direct replacement in select Mazda applications. It provides the ECU with the exhaust feedback needed for accurate fuel control and emissions monitoring, including upstream sensor positions on 2019-2025 Mazda 3, CX-30, CX-5, and CX-50 models.

Walker Products has developed this OE Base Sensor line as an original-equipment-style replacement for application-specific fitment and diagnostic performance. If your Mazda 3, CX-30, CX-5, or CX-50 is showing fuel trim issues, a MIL light, or drivability concerns tied to the upstream air-fuel sensor, part number 250-25175 is built around the vehicle’s required sensor configuration.

• Heated wide-band oxygen sensor for upstream placement
• Specific fitment for the listed Mazda applications
• 5-wire design with rectangle connector
• M18 x 1.5 thread size and 22 mm wrench size
• Supports ECU feedback for air-fuel ratio and emissions control

Product Line Details

The Walker OE Base Sensor line focuses on application-matched engine management sensors for vehicles that require precise diagnostic feedback. For this part number, the sensor design, connector style, and thread specification are matched to the listed Mazda fitments rather than being a universal replacement.

Vehicle Fitment

• Fits 2019-2025 Mazda 3, Upstream, OE Base Sensor
• Fits 2021-2025 Mazda CX-30, Upstream, OE Base Sensor
• Fits 2022-2025 Mazda CX-5, Upstream, OE Base Sensor
• Fits 2023-2025 Mazda CX-50, Upstream, OE Base Sensor

What It Helps Address

• Check engine light related to upstream oxygen or air-fuel sensor faults
• Poor engine performance caused by incorrect exhaust feedback
• Increased fuel consumption from inaccurate mixture control
• Elevated exhaust emissions from a failing sensor signal
• Diagnostic trouble codes stored in the ECU for sensor-related faults

Installation Notes

Confirm the upstream position, connector shape, wire count, and thread size before installation. Inspect the sensor harness and connector for heat damage, corrosion, or broken terminals, since wiring issues can shorten sensor life or trigger false fault codes. Verify the vehicle application by year, make, model, and position before ordering.

Quality Assurance

Walker Products manufactures engine management and oxygen/air-fuel sensors as OE-style replacement parts and operates under ISO 9001/TS 16949 quality systems. Part number 250-25175 is engineered for the specified application and diagnostic requirements of the ECU.