NTK 24731 Air / Fuel Ratio Sensor - Upstream

NTK Direct Fit A/F Sensor for Mazda

NTK Part Number 24731 is a direct-fit, heated wide-band air/fuel ratio sensor built for precise upstream fuel control. It is an OE-equivalent replacement for select Mazda MX-5 Miata and Mazda 2 applications, helping the engine control unit read mixture changes accurately and adjust fueling in real time.

The NTK Direct Fit 4-Wire A/F Sensor line is engineered as a standard replacement solution with vehicle-specific fitment, factory-style connector design, and the sensor technology needed for modern closed-loop engine management.

Key Features

• Direct-fit air/fuel ratio sensor for specific Mazda applications
• Wide-band sensor technology for linear air/fuel feedback
• Heated design for faster operating response
• 4-wire A/F sensor construction
• Female connector with black housing
• M18 x 1.5 thread size with 7/8 in. (22 mm) hex
• Upstream position application
• Standard replacement grade

Detailed Description

NTK 24731 is designed for vehicles that rely on a wide-band upstream sensor to monitor air/fuel ratio with greater precision than a conventional switching oxygen sensor. By sending a linear signal to the ECU, the sensor supports continuous fuel-trim correction for stable combustion, efficient operation, and lower emissions. This part is listed for 2006-2015 Mazda MX-5 Miata, upstream, and 2011-2014 Mazda 2, upstream. It is a direct-fit replacement for drivers searching for an OE-style Mazda MX-5 Miata upstream air/fuel ratio sensor or a Mazda 2 upstream wide-band sensor.

NTK is known for OEM oxygen sensor manufacturing and ceramic sensor technology, with control over the ceramic element from raw material through finished product. Part number 24731 is built to match the original application requirements for the Mazda MX-5 Miata and Mazda 2, making it a practical choice when replacing a worn or failing upstream sensor. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Common Issues This Sensor May Address

• Check engine light related to air/fuel ratio or oxygen sensor faults
• Rough idle or unstable fuel control
• Poor fuel economy caused by inaccurate mixture feedback
• Delayed or incorrect ECU fuel-trim response
• Emissions test failure tied to upstream sensor performance

Installation Notes and Tips

Confirm the upstream sensor location before installation and verify connector shape, thread size, and harness length against the original part. Use proper oxygen sensor service tools to avoid damaging the sensor body or wiring, and inspect the exhaust threads for corrosion or contamination before threading in the replacement. Clear diagnostic trouble codes after installation and verify live data to confirm normal sensor response.

Quality Assurance

NTK supplies OEM oxygen sensors and uses application-specific engineering for direct-fit replacement parts. Part Number 24731 is built to OE-equivalent design standards for the listed Mazda applications and sensor type.