OT:RR:NC:N1:105
Edward Hayes
Leake Andersson, LLP
1100 Poydras Street, Suite 1700
New Orleans, LA 70163
RE: The country of origin of a mass air flow sensor
Dear Mr. Hayes:
In your letter dated June 26, 2025, on behalf of your client, Bometec (Thailand) Company, Ltd., you
requested a country of origin ruling on a mass air flow sensor.
The item under consideration is described as a mass air flow (MAF) sensor, 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 heated wire or a hot film element. As
the air flows over the heated element, it cools down. The sensor measures this cooling effect and converts it
into an electrical signal. The measure of the signal corresponds to the mass of the airflow. The MAF sensor
sends this information to the ECU, which uses it in conjunction with other sensor data to make real-time
adjustments to fuel injection, ignition timing, and other engine parameters. By continuously monitoring and
adjusting the air-fuel mixture, the MAF sensor helps ensure that the engine runs smoothly, efficiently, and
within the desired operating range.
The MAF sensor at issue will be manufactured in Thailand from unfinished component parts sourced from
various countries including the United States, Thailand, China, Malaysia, South Korea, India, Taiwan, and
Germany. After the unfinished component parts are imported into Thailand, they will undergo a series of
highly specialized modifications during the production process to ultimately create the MAF sensor.
The MAF sensor includes plastic particles and glue sourced from South Korea. The integrated chip, solder
paste, boxes, tape, pallet and wrapping are made in Thailand. An additional integrated chip is made in the
United States. The resistors and diodes are made in Taiwan, while the aluminum wire is made in Malaysia,
and the triodes are made in Germany. There is also glue made in India. The printed circuit board (PCB),
some resistors and diodes, electric capacity, Negative Temperature Coefficient (NTC) resistor, Resistance
Temperature Detector (RTD), Low-Power Temperate-Compensated (LPTC) resistor, aluminum plate, metal
pins, wire mesh cover, screws, additional glue, an electrostatic bag, desiccant, as well as labels and other
packing materials, are sourced from China.
The process starts when the raw materials, including the electronic components, metal parts, and plastics, are
delivered to the facility, unloaded from the truck, and opened for inspection. Once approved, materials are
manually stored in the warehouse to await production. Next, the external plastic housing components are
manufactured on-site using injection molding machines. Then, the printed circuit boards (PCBs) are baked in
an oven before being populated with electronic components using surface mount technology (SMT) and
soldering. The electronic components include resistors, capacitors, diodes, transistors, and CPU chips. The
CPU chips are programmed via a tape-out programming machine with application-specific software, enabling
it to process airflow data and execute embedded algorithms, turning it into a complete printed circuit board
assembly (PCBA). The completed PCBAs are then optically inspected prior to laser cutting to ensure
soldering accuracy and board precision.
The component parts and subassemblies are then assembled into a complete MAF sensor in Thailand. The
LPTC resistor, RTDs, and NTC resistor are welded to the PCBA. Then, glue is dispensed onto the insert core
while also bonding the housing pins to the PCBA using wire bonding. The pin interfaces and the PCBA are
then soldered. Next, the PCBA is placed in a test fixture where flow rate data is downloaded to the CPU
using a software handshake protocol. This ensures each sensor can generate calibrated, non-linear outputs
with less than 3% deviation. Additional steps include aging in a high-temperature oven, mechanical
fastening, glue application, mesh and housing assembly, and two-point functional testing to ensure consistent
performance. Final operations include laser marking, cleaning, visual inspection, and packaging.
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, it is our opinion that the assembly process performed in
Thailand is considered complex and results in a substantial transformation of the different components. The
creation of the PCBA in Thailand using SMT, including the downloading of the software, generates a
working PCBA capable of performing measurements. It is our opinion that this is a new and different article
of commerce with a name, character, and use distinct from the individual components. Accordingly, the
country of origin of the MAF sensors will be Thailand, which is where the PCBA creation and programming
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 [email protected].
Sincerely,
(for)
James Forkan
Acting Director
National Commodity Specialist Division