The country of origin of an oxygen sensor

N357041 January 6, 2026 OT:RR:NC:N1:105 CATEGORY: Origin Hui Wang TradeSmart USA LLC 1370 Valley Vista, Suite 200 Diamond Bar, CA 91765 RE: The country of origin of an oxygen sensor Dear Mr. Wang: In your letter dated December 15, 2025, on behalf of your client, Accauto (Thailand) Co., Ltd, you requested a country of origin ruling on an oxygen sensor. Descriptive literature was provided for our review. The item under consideration is described as an oxygen sensor, which is designed for modern engines to monitor the oxygen concentration in engine exhaust and convert it into an electrical signal. The signal is fed back to the electronic control unit (ECU) to adjust the air-fuel ratio, ensuring vehicle emissions meet environmental standards, and optimal engine and emissions system performance. The oxygen sensor is ultimately used in passenger vehicles, medium and heavy-duty trucks, and commercial vehicles, as well as all-terrain vehicles and utility task vehicles. The construction of the oxygen sensor includes parts from Thailand, China, and Japan. The wire harness includes a Chinese or Thai plug, Chinese waterproof plug, leather hose, terminal block, wire connector, rubber wire sheath, shell, back cover, and Japanese wires. The probe assembly includes a Chinese inner protection tube, outer protection tube, house seal, ceramic base A, ceramic base B, dust cover, sealed powder, and chip. The house could be procured in China or Thailand. Finally, the Chip is manufactured in Thailand using parts from Japan and Thailand. The Japanese components include the binder, plasticizer, protective layer slurry, catalytic electrode platinum paste, lead platinum paste of heater, pin platinum paste, heating platinum paste of heater, zirconia powder, and alumina powder. Finally, the Thai components are the xylene solvent and alcohol solvent. The oxygen sensor is manufactured utilizing four main modules that are all produced in Thailand. The manufacturing process starts with the probe assembly, which is composed of six (6) key components: the ceramic sensitive element, hexagonal base, protective tube, ceramic seat A, ceramic seat B, and sealing ring. The process begins with pressing the protective tube onto the base to create the hexagonal base body, followed by inserting the ceramic element through the seats and sealing ring to form the core assembly. This core is then placed into the hexagonal base and secured through riveting and sealing, completing the probe assembly. The finished probe undergoes electrical, dimensional, and air tightness tests on a fully automated assembly line, and only units that pass all inspections are accepted as qualified products. Next, is the chip core manufacturing process, which is organized into six (6) main stages encompassing a total of seventeen (17) steps. It begins with raw material preparation, where ceramic powder is dried, batched with binders and solvents, and milled into a uniform slurry. The second stage focuses on film formation through tape casting, cutting, and drying to create stable ceramic sheets. In the third stage, the films are mounted, punched, printed with circuit patterns, and laminated into multilayer assemblies. Compaction and shaping follow, with vacuum sealing, warm isostatic pressing, and hot cutting to form consolidated cores. The fifth stage involves binder removal and high-temperature sintering to densify the ceramic, followed by thorough performance testing to ensure quality. Finally, the process concludes with packaging and warehousing, ensuring qualified chip cores are ready for integration into larger assemblies. Then, the wiring harness assembly is built from eight components (8) including the plug housing, wire, leather tube, rubber part, shell, terminal block, ceramic wire cover, and waterproof plug, and is combined in a structured process. It progresses through four main stages and nine steps, from wire cutting and crimping to threading, plug integration, and final inspection, resulting in a complete and reliable harness assembly. Stage 1: Wire Preparation The process begins with cutting rolled wire to the required length using an automatic wire cutting and terminal crimping machine. One end of the wire is simultaneously crimped with a terminal block, while the opposite end is treated with tin dipping. To ensure mechanical strength and reliability, the crimped terminal block undergoes a tension test before moving forward. Stage 2: Threading and Component Assembly Wires of different colors are threaded sequentially through the leather tube, shell, rubber part, and ceramic wire cover. The terminal block is then secured onto the ceramic wire cover using dedicated tooling, which ensures correct positioning and reliable contact with the pins of the ceramic sensitive element. Stage 3: Waterproof Plug Integration On the opposite side of the wire, a waterproof plug is installed in the designated position. The plug’s terminal block is crimped and locked firmly in place. Each colored wire is then inserted into its corresponding hole within the plug housing, creating an organized and secure connection. Stage 4: Final Inspection and Completion A second tension test is performed to verify the stability of the plug terminal blocks inside the plug housing. Only after this quality inspection is passed is the wiring harness assembly considered complete and ready for integration with the probe assembly. The final assembly in Thailand integrates the wiring harness components with the probe components to form the complete oxygen sensor. The wiring terminals of the harness are connected to the electrode pins of the ceramic sensitive element inside the probe, enabling signal transmission from the sensor to the ECU. Once electrical continuity is established, the shell of the wiring harness is pressed onto the hexagonal base of the probe using an air press. The protective tube and shell are then permanently joined to the base through laser welding, while the rear end of the shell is secured by riveting. This sequence produces the finished oxygen sensor, which is subsequently tested on a comprehensive combustion test bench to verify signal accuracy and overall performance. Only units that pass all tests are released to the packaging process. The packaging process begins with pressing the sealing ring onto the housing, followed by applying an anti-nickel seizing agent to the threaded section. A dust cover is then fitted over the threads to provide additional protection. Afterward, laser marking is applied according to customer specifications for product identification and traceability. Finally, the sensor is wrapped in a shockproof bag and placed into an inner box, ensuring safe handling and storage before shipment. The “country of origin” is defined in 19 CFR 134.1(b) as “the country of manufacture, production, or growth of any article of foreign origin entering the United States. Further work or material added to an article in another country must effect a substantial transformation in order to render such other country the ‘country of origin’ within the meaning of this part.” 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, 69 C.C.P.A. 151 (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). In regard to the country of origin of the oxygen sensor, it is our opinion that the assembly process performed in Thailand is considered complex and constitutes a substantial transformation. Each subassembly is created from foreign components and combined in Thailand to create a complete oxygen sensor. In our opinion, this manufacturing creates a new article that is different than the individual components sourced from Thailand, China, and Japan. Accordingly, the country of origin of the oxygen sensor will be Thailand, which is where the functional subassemblies are created and the overall sensor is manufactured. 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