Frankfurt/San Francisco:  BMW (BMWG.DE) and Apple (AAPL.O) may rekindle a courtship put on hold after an exploratory visit by executives of the world’s top maker of electronic gadgets to the headquarters of the world’s biggest seller of premium cars.

Apple Chief Executive Tim Cook went to BMW’s headquarters last year and senior Apple executives toured the carmaker’s Leipzig factory to learn how it manufactures the i3 electric car, two sources familiar with the talks told Reuters.

The dialogue ended without conclusion because Apple appears to want to explore developing a passenger car on its own, one of the sources said.

Also, BMW is being cautious about sharing its manufacturing know-how because it wants to avoid becoming a mere supplier to a software or internet giant.

During the visit, Apple executives asked BMW board members detailed questions about tooling and production and BMW executives signalled readiness to license parts, one of the sources said. News of the Leipzig visit first emerged in Germany’s Manager-Magazin last week.

“Apple executives were impressed with the fact that we abandoned traditional approaches to car making and started afresh. It chimed with the way they do things too,” a senior BMW source said.

The carmaker says there are currently no talks with Apple about jointly developing a passenger car and Apple declined to comment. However, one of the sources said exploratory talks between senior managers may be revived at a later stage.

It is too early to say whether this will be a replay of Silicon Valley’s Prometheus moment: The day in 1979 when Apple co-founder Steve Jobs visited Xerox’s Palo Alto Research Centre where the first mouse-driven graphical user interface and bit-mapped graphics were created, and walked out with crucial ideas to launch the Macintosh computer five years later.

BMW has realized next-generation vehicles cannot be built without more input from telecoms and software experts, and Apple has been studying how to make a self-driving electric car as it seeks new market opportunities beyond phones.