The country of origin of a mass air flow sensor

N357186 January 9, 2026 OT:RR:NC:N1:105 CATEGORY: Origin Timothy Laderach Crowell and Moring LLP 1001 Pennsylvania Ave. NW Washington, D.C., DC 20004 RE: The country of origin of a mass air flow sensor Dear Mr. Laderach: In your letter dated December 18, 2025, on behalf of your client, CrossCon Industries LLC, you requested a country of origin ruling on a mass air flow sensor. Descriptive literature was provided for our review. The item under consideration is described as a mass air flow (MAF) sensor (item no. DK-AF272S-P), which is a device used in the automotive industry to measure the amount of air entering the engine. The information obtained by the sensor is used by the engine control unit (ECU) to calculate and deliver the appropriate amount of fuel for efficient combustion. The MAF sensor helps ensure the correct air-fuel ratio, which is essential for optimal engine performance, fuel efficiency, and emissions control. The MAF sensor achieves the appropriate air fuel ratio by utilizing a platinum heated wire or a hot film element, also referred to as a Resistance Temperature Detector (RTD). The RTD is heated by an electrical current from the printed circuit board assembly (PCBA). The heated RTD is exposed to the air flow through a channel in the MAF sensor’s plastic housing. As the air flows through the channel, the heating element’s temperature changes, causing either current or voltage changes within the MAF sensor. The MAF sensor’s microcontroller unit (MCU) monitors the changes in current or voltage and translates this information into an air quantity signal. An MCU is essentially a small, specialized computer on a single integrated circuit (IC) chip. It is designed to control specific operations within an embedded system, such as an MAF sensor. An MCU is further made up of several smaller key components, four of which are the Central Processing Unit (CPU), the memory (both read-only memory (ROM) and random access memory (RAM)), the input/output peripherals, and a clock. The signal from the MCU is then sent to vehicle’s engine ECU. The CPU, as with other computer chips, is the brain of the MCU. It is responsible for executing instructions from the vehicle’s ECU. The ROM stores the MAF Sensor’s firmware while the RAM stores critical temporary data for successful operation of the MAF Sensor. Input and output peripherals allow the MCU to interact with the external world, such as reading sensor data or controlling actuators. And finally, the clock provides the timing signals that control the MCU’s operation. In your letter, you present two scenarios where the manufacturing process is the same but the raw materials are sourced from different locations. In scenario one, the operational amplifier and audion are sourced from the Philippines, while the remaining items are all sourced from China including the printed circuit board, capacitors, resistors, diodes, voltage stabilizer module, MCU, raw plastic, aluminum sheet, insulation pad, O-ring, thermistors, RTD, nickel-plated brass sheet material, stainless-steel nickel-plated sheet material, copper band, packing material, glue, and bonding wires. In scenario two, all of the raw materials from scenario one are produced in Thailand except for the raw plastic, aluminum sheet, insulation pad, O-ring, thermistors, RTD, nickel-plated brass sheet material, stainless-steel-nickel-plated sheet material, copper band, packing material, glue, and bonding wires, which are produced in China. Based on your detailed description, the manufacturing of the Printed Circuit Board Assembly (PCBA) occurs in Thailand through a twenty-step process utilizing Surface Mount Technology (SMT). This intricate process begins with the placement of the PCB board, followed by the precise application of solder paste, mounting of various components (resistors, capacitors, chips), and manual placement of larger or irregular components. Multiple inspections are conducted throughout this stage to ensure quality, including checks for defects, proper component placement, and reliable soldering. Further steps involve separating multi-up automotive PCBs, inserting through-hole components, and mass soldering of DIP components, with manual re-soldering for special or reworked parts. The process concludes with cleaning, testing, and packing of the PCBA. Crucially, at the completion of this Thai manufacturing stage, the PCBA acquires the essential functionality of the MAF sensor, specifically its ability to convert a raw thermal signal into an analog or digital output. Subsequently, the finished PCBA is shipped to China for further manufacturing. In China, the PCBA is manually integrated into a China-made plastic housing containing embedded wires. An RTD is attached to the PCBA using die-bonding or welding, and a silicon-based sealant is applied before the housing is closed with an O-Ring. The final steps in China involve inspection, packing, and preparation for import into the United States. When determining the country of origin, the substantial transformation analysis is applicable. See, e.g., Headquarters Ruling Letter H301619, dated November 6, 2018. The test for determining whether a substantial transformation will occur is whether an article emerges from a process with a new name, character, or use different from that possessed by the article prior to processing. See Texas Instruments Inc. v. United States, 681 F.2d 778 (C.C.P.A. 1982). This determination is based on the totality of the evidence. See National Hand Tool Corp. v. United States, 16 C.I.T. 308 (1992), aff’d, 989 F.2d 1201 (Fed. Cir. 1993). Regarding the country of origin of the MAF sensor. For scenario one, it is our opinion that the assembly process performed in Thailand is considered complex and results in a substantial transformation of each raw material. The creation of the PCBA in Thailand, utilizing surface mount technology, yields a functional PCBA capable of performing measurements, which is central to the completed sensor’s character and use. The subsequent assembly operations performed in China do not transform the PCBA into a new and distinct article of commerce, possessing a name, character, and use different from its individual components. Therefore, the country of origin for the MAF sensor (item no. DK-AF272S-P) in scenario one will be Thailand, where the critical PCBA creation occurs. Similarly, in scenario two, additional raw materials are sourced from Thailand. While they do not require to be substantially transformed, they reinforce the origin of the PCBA to be Thailand. The subsequent assembly performed in China, as in scenario one, does not transform the Thai-originated PCBA into a new and distinct article of commerce with a name, character, and use separate from its constituent components. Accordingly, the country of origin for the MAF sensor (item no. DK-AF272S-P) in scenario two will be Thailand, where the critical PCBA creation occurs. The holding set forth above applies only to the specific factual situation and merchandise description as identified in the ruling request. This position is clearly set forth in Title 19, Code of Federal Regulations (CFR), Section 177.9(b)(1). This section states that a ruling letter is issued on the assumption that all of the information furnished in the ruling letter, whether directly, by reference, or by implication, is accurate and complete in every material respect. In the event that the facts are modified in any way, or if the goods do not conform to these facts at time of importation, you should bring this to the attention of U.S. Customs and Border Protection (CBP) and submit a request for a new ruling in accordance with 19 CFR 177.2. Additionally, we note that the material facts described in the foregoing ruling may be subject to periodic verification by CBP. This ruling is being issued under the provisions of Part 177 of the Customs and Border Protection Regulations (19 C.F.R. 177). A copy of the ruling or the control number indicated above should be provided with the entry documents filed at the time this merchandise is imported. If you have any questions regarding the ruling, please contact National Import Specialist Jason Christie at jason.m.christie@cbp.dhs.gov. Sincerely, (for) Evan Conceicao Designated Official Performing the Duties of the Division Director National Commodity Specialist Division