Aikawa told reporters at the transport ministry he will see through the investigation of the scandal, which surfaced last month.
He appeared with Mitsubishi Chairman Osamu Masuko, who helped engineer a deal with Japanese rival Nissan Motor Co., to take a 34 per cent stake in Mitsubishi for 237 billion yen ($2.2 billion). Mitsubishi stock had plunged more than 30 per cent after the scandal.
Nissan found the faked mileage tests because of a discrepancy with its own tests on Mitsubishi-manufactured minicar models with tiny engines that had been sold under the Nissan brand.
Mitsubishi says rigging goes back 25 years, and may involve all models, including discontinued ones.