The precise nature of the investigation could not be confirmed. Typically, however, DCIS export investigations focus on whether a company violated the Arms Control Export Act by sending overseas products or technical specifications for items on the U.S. Munitions List without first obtaining a U.S. government license. The sensors and F-35 specifications in this case may be subject to the U.S. Munitions List. In terms of import violations, DCIS often investigates whether companies have engaged in fraud by misleading the Pentagon as to the origin of foreign parts.
The case throws a spotlight on the reliance of American companies, even in sensitive areas, on China as a manufacturing base for basic components. In the past 20 years, much production has been shifted out of the United States to lower cost areas, particularly China.
The sensors are part of the power thermal management system that Honeywell builds to cool the F-35, start its engines and pressurize the cabin, said Joe DellaVedova, spokesman for the Pentagon's F-35 program office.
(Read more: The new Humvee: Lockheed, Oshkosh, AM General bid on defense)
Honeywell spokesman Scott Sayres said the company decided in late 2012 - after consulting with Lockheed and the Pentagon - to move production of the sensors used on the F-35 from China to a plant in Boyne City, Michigan. It funded the move at its own cost, he said.
Honeywell made the move after the origin of the sensors was discovered during a comprehensive review of the supply chain for the F-35, the newest U.S. warplane.
That was carried out by Lockheed after another key supplier, Northrop Grumman, discovered it had used non-compliant magnets made in Japan in building the jet's advanced radar system.
Pentagon acquisition chief Frank Kendall also issued a waiver for those parts.
Sayres said the sensors were part of a basic circuit card used in products sold commercially around the world.
"We firmly believe Honeywell has complied with all applicable U.S. laws and regulations relating to the manufacture of the component in China," Sayres said.
Officials at the Justice Department and Pentagon declined to comment on the reported Honeywell investigation.
One of the three sources familiar with the probe, who were not authorized to speak publicly, said it was focused on Honeywell's processes and procedures, rather than the components involved.
They were seen as low risk items that did not pose any security risk for the F-35 program.