NTK 25264 Oxygen Sensor - Downstream

Direct-fit oxygen sensor for Mercedes-Benz

NTK 25264 is a direct-fit, heated narrow-band oxygen sensor built for specific Mercedes-Benz applications. It provides closed-loop feedback to the ECU to help maintain air-fuel control, support fuel efficiency, and monitor emissions system performance.

Key features

• Direct-fit replacement for specific downstream applications
• Heated narrow-band, switching zirconia sensor design
• 4-wire layout with blade terminals and oval connector
• Threaded M18 x 1.5 mounting with 7/8 in. hex size
• Standard replacement grade for emission control service

Product details

NTK 25264 is part of the Direct Fit Oxygen Sensor line, which focuses on application-specific replacement sensors for emission control service. As an OEM oxygen sensor manufacturer, NTK applies ceramic-element manufacturing control from raw material through finished sensor construction. This oxygen sensor is used in downstream positions on Mercedes-Benz C300, CLA250, GLC300, GLE350, A220, and related models listed in the fitment data, where accurate exhaust feedback is needed for OBDII monitoring and air-fuel regulation. This part cross-references Mercedes-Benz OE numbers 0005427300 and 0005428104 for the same application.

What this part helps address

• Fault codes related to oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Reduced fuel economy caused by inaccurate exhaust readings
• Emission monitoring issues tied to downstream sensor response
• Catalytic converter efficiency warnings in OBDII diagnostics

Installation notes and tips

Confirm the connector shape, thread size, and wire count against the original sensor before installation. This sensor uses a threaded mount and a specific harness length, so routing and connector orientation should match the vehicle’s original setup. Verify downstream placement and compare the OE reference numbers 0005427300 and 0005428104 before ordering.

Quality assurance

NTK is a major OEM oxygen sensor supplier and uses controlled ceramic-element manufacturing for OE application coverage and consistent sensor construction.