Walker 250-54039 Oxygen Sensor - Upstream

Walker OE Oxygen Sensor for Mazda 6

Walker Products OE 250-54039 is a heated upstream oxygen sensor built for specific vehicle applications and ECU feedback requirements. It is engineered as an OE-style replacement for the 2006-2008 Mazda 6 with California emissions ESV coverage, making it a direct-fit option for the upstream sensor location.

The Walker Products OE line focuses on application-specific engine management sensors, with fitment matched to the vehicle position and connector design. For Mazda 6 owners diagnosing fuel trim or emissions-related faults, 250-54039 provides the correct sensor format for the upstream exhaust stream.

Key Features

• Heated oxygen sensor for faster operating temperature and signal response
• Specific-fit design for the upstream position
• 4-wire configuration with 20-gauge wiring
• Radiused polygon male connector for application-specific connection
• 18.0 mm thread diameter with threaded mounting
• 22.17 in. wiring harness length and 25.71 in. overall length
• Walker Products OE part number 250-54039

Detailed Description

Walker Products OE 250-54039 is an oxygen sensor for the 2006-2008 Mazda 6, upstream, including California emissions ESV vehicles. As a heated sensor, it helps the ECU monitor exhaust oxygen content after startup and supports accurate air-fuel control. The specific-fit construction, connector shape, and harness length are matched to the listed application for straightforward replacement of the original sensor.

Walker Products has supplied engine management and oxygen/air-fuel sensors for decades, and the Walker Products OE line is built around application-specific replacement parts for modern emissions systems. If you are replacing a failing upstream oxygen sensor on a Mazda 6, part number 250-54039 is the correct OE-style reference to verify against your vehicle’s emissions package and connector layout.

What It Helps Fix

• Check engine light related to upstream oxygen sensor faults
• Poor fuel economy caused by inaccurate exhaust feedback
• Rough engine operation from incorrect air-fuel correction
• Elevated exhaust emissions from a degraded sensor signal
• Stored ECU fault codes tied to the oxygen sensor circuit

Installation Notes

Before replacement, inspect the sensor wiring harness and connector for heat damage, abrasion, or corrosion. Confirm the upstream location, thread size, connector style, and California emissions ESV application before installation. Use the vehicle’s service information to verify the exact sensor position and clear diagnostic trouble codes after repair if required.

Quality Assurance

Walker Products OE sensors are manufactured as application-specific replacements for modern engine management systems. Walker Products is ISO 9001/TS 16949 certified, and the brand has supported automotive sensor and fuel system applications since 1946.