Harman International, which supplies radios to Fiat Chrysler, said the hacking risk that led the carmaker to recall 1.4 million vehicles last month seemed like an isolated case.
"We do not believe this problem exists in any other car outside of Fiat Chrysler," Harman Chief Executive Dinesh Paliwal told Reuters.
Harman's infotainment system -- a clutch of hardware devices installed in vehicles to provide audio, video and navigation systems -- was part of Fiat Chrysler's Uconnect system, which uses hardware, software and network connectivity provided by other companies.
Fiat Chrysler could not be immediately reached for comment.
Two veteran cybersecurity researchers recently used a feature in the Fiat Chrysler telematics system Uconnect to break into a Jeep Cherokee being driven on the highway by a reporter for technology news site Wired.com.
The controlled test sharply escalated the debate about the safety of increasingly connected cars and trucks.
Read More: Car Hacking Risk Could Extend Beyond Fiat Chrysler: NTSB Chief
The National Highway Traffic Safety Administration said it was trying to determine how many carmakers have received radios from Harman. The regulator estimated that Harman has supplied infotainment systems to about 2.8 million vehicles.
"We have told them [NHTSA] that this situation seems to be isolated to just Chrysler," Paliwal said.
Paliwal said Harman does not anticipate any financial impact related to the recall. Reuters