Car Oxygen Sensor Lambda Sensor O2 Snesor Part Number 39210-2M425 For Hyundai / Kia

This Lambda Sensor (Oxygen Sensor) is an Original Equipment (OE) component manufactured for Hyundai and Kia vehicles. The OE number 39210-2M425 is the primary reference for this sensor, which is widely used as a downstream (post-catalyst / rear / lower) oxygen sensor across multiple Hyundai and Kia models equipped with 1.6L turbocharged and 1.6L hybrid petrol engines.

The sensor monitors oxygen content in the exhaust gases and relays this information to the Engine Control Unit (ECU) to ensure the optimal air-fuel mixture is maintained for efficient combustion and reduced emissions. It features a heated, 4-wire design with a 4-pin connector, allowing it to reach operating temperature quickly for precise air-fuel ratio measurement.

This sensor is a direct-fit component featuring a vehicle-specific electrical connector and pre-terminated wiring, eliminating the need for cutting or splicing during installation. It is positioned after the catalytic converter (downstream / post-catalyst / rear / lower) and serves as a diagnostic probe for catalyst efficiency monitoring.

• This is a 4-wire heated oxygen sensor manufactured by Hyundai Kefico Corporation (the OEM supplier) to Hyundai and Kia's original equipment standards.
• The built-in heating element quickly brings the ceramic sensing tip up to operating temperature after a cold start, enabling the ECU to enter closed-loop fuel control sooner and reduce cold-start emissions.
• As a downstream (post-catalyst / rear / lower) diagnostic sensor, it is installed after the catalytic converter and monitors catalyst efficiency by comparing its signal with the upstream sensor.
• The sensor measures oxygen concentration in exhaust gases and sends voltage signals to the ECU for air-fuel ratio optimization. For zirconium-type sensors, output voltage is approximately 0.6 – 1.0 V under rich conditions, and near 0 V under lean conditions.
• The sensor features a 4-pin connector with a cable length of approximately 405 mm.
• All sensors are manufactured to meet or exceed original equipment quality standards.
• Also known as: O2 Sensor, Lambda Sensor, Lower Oxygen Sensor, Rear Oxygen Sensor, Sensor Assembly Oxygen.

The following OE numbers are directly interchangeable or closely related to 39210-2M425. Always verify physical fitment (connector shape, cable length and thread size) with your original part before purchasing.

• 39210-2M412 is the front (upstream / pre-catalyst) oxygen sensor counterpart for many of the same Hyundai and Kia vehicle applications. This part (39210-2M425) is the rear (downstream / post-catalyst / lower) sensor.
• The related OE numbers listed above are similar sensors used on other Hyundai and Kia engine variants and model years.
• 9025090037 and 9025080037 are alternative reference numbers used by some suppliers for this sensor.
• Always physically compare your old sensor's connector shape (4-pin), cable length (405 mm), and thread size (M18 × 1.5) before purchasing.

This Lambda Sensor is an original equipment component used across a range of Hyundai and Kia vehicles. Based on extensive cross-reference data, the sensor is installed in the downstream (post-catalyst / rear / lower) position.

• This is a downstream (post-catalyst / rear / lower) oxygen sensor. It is installed after the catalytic converter and serves as a diagnostic probe for catalyst efficiency monitoring.
• Primary applications include Hyundai Elantra (2020-2025), Hyundai Sonata (2019-2023), Hyundai Santa Fe (2020-2024), Hyundai Tucson (2020-2025), Hyundai Kona (2021-2023); Kia K5 (2021-2024), Kia Seltos (2024-2026), and Kia Sorento (2021-2024) with 1.6L turbocharged and 1.6L hybrid engines.
• How to verify: Locate your vehicle's catalytic converter. This sensor is installed in the pipe after the catalytic converter. If your faulty sensor is located before the converter, you need the upstream sensor 39210-2M412 instead.
• Not compatible with diesel engines — diesel applications use different sensors with different calibration parameters.
• The vehicle fitment information above is a guide only. Always confirm compatibility using your vehicle's VIN or by physically inspecting your old sensor's position, connector shape, and cable length before ordering.