When Toyota launched a quirky Twitter campaign depicting the car parts of its new Prius hybrid using anime girls earlier this year, the digital advertising impact was instant. The oddity and boldness attracted young Japanese users of social media that had not been effectively targeted by Toyota’s traditional, celebrity-heavy TV commercials. As with almost all of Toyota’s ads, the campaign’s creator was Dentsu.

The Prius tweets were not part of the overcharging scandal that shook Japan’s most powerful advertising agency last week. But it was not coincidental that Toyota was the company that discovered the irregularities.

The revelation followed a meticulous analysis of digital ad impact by a company grappling to connect with a home market that has shown declining interest in owning cars. The analysis was disappointing, prompting the automaker to question if whether Dentsu was placing the digital ads properly.