Top executives at Mitsubishi Motors are resigning, weeks after the company admitted it falsified fuel economy tests affecting hundreds of thousands of cars.

President Tetsuo Aikawa and Vice President Ryugo Nakao will step down from their posts on June 24 at a general shareholder's meeting, the company announced Wednesday.

Mitsubishi (MSBHF) said last month it had fudged fuel efficiency tests in a scandal that has now spread to 13 models and goes back a quarter century. Investors have reacted by erasing roughly 32% of the company's stock value over the past month.

The fallout has continued to widen, putting the company's financial prospects at risk. Just last week, one of Japan's big three automakers, Nissan (NSANF), said it would make a $2.2 billion investment in Mitsubishi, becoming its largest shareholder in an effort to help steer the company out of its crisis.

Related: Nissan to sink $2.2 billion into scandal-ridden Mitsubishi Motors

Mitsubishi said its initial investigation showed that company managers were under intense pressure to keep pace with fuel economy rates reported by competitors, and used a procedure to calculate efficiency that did not comply with Japanese law. It has admitted it faces a difficult job to rebuild trust with customers.

The Mitsubishi scandal prompted the Japanese government to ask other automakers in the country to review their fuel emissions and economy tests.

On Wednesday, Suzuki Motor apologized for using an improper testing method on 16 of its models.

The company said that a fuel economy testing method didn't comply with Japanese government regulations, but that an internal investigation found no evidence of manipulation. It said it saw no need to revise the fuel efficiency data because they don't differ significantly from the results of approved tests it has since carried out.

Suzuki's stock dropped 9.4% Wednesday on news of the incorrect testing.

Related: Is Nissan-Mitsubishi a new rival for GM and Toyota?

Other automakers have been penalized in recent years for putting a rosy spin on fuel economy figures.

Korean carmakers Hyundai and Kia agreed to pay a combined $100 million fine in the U.S. in 2014 for overstating fuel economy estimates for many of their vehicles. They also had to refund customers for the difference in estimated fuel costs.

That same year, Ford said it would compensate owners of about 200,000 U.S. vehicles after discovering the cars' gas mileage was overstated.

--Junko Ogura and Jethro Mullen contributed to this report