The German Federal Cartel Office said it had warned Google's parent company Alphabet in a preliminary legal assessment that it "intends to prohibit" various "anti-competitive practices" linked to Google Automative Services (GAS).
The GAS platform, licensed to vehicle manufacturers, comprises Google Maps, a version of the "Google Play" app store and the Google voice assistant.
"In particular, we take a critical view of Google offering its services for infotainment systems as a bundle only, as this reduces its competitors' chances to sell their competing services as individual services," Andreas Mundt, head of the Federal Cartel Office, said in a statement.
Google now has the opportunity to respond to the allegations, it added.
The watchdog last year already opened an investigation into Google Maps, to determine whether restrictions on combining the platform with third-party map services were harming competition.
That probe is still ongoing.
The Federal Cartel Office last year classed Alphabet as a company of "paramount significance for competition across markets," allowing for closer monitoring for possible abuse of its market position.
Fellow tech behemoths Amazon, Apple and Meta have also been placed under increased scrutiny, made possible by new German legislation.
The German Competition Act, which came into force in 2021, gives the Federal Cartel Office greater powers to clamp down on anti-competitive behavior by tech giants.