An investigative committee found irregularities during horsepower output testing, which took measurements based on computer modules running software that differed from that used for mass production, resulting in values with less variation, the carmaker said in a statement Monday.

The certification issue the latest to beset Toyota, following an announcement by subsidiary Daihatsu Motor Co last month that most of its vehicles weren’t properly tested for collision safety and that the carmaker manipulated the results of tests dating as far back as 1989. As a result, Daihatsu is halting shipments and suspending operations through January.

“Going forward, we will be involved in all companywide activities to help rebuild Toyota Industries and review the situation to thoroughly ensure that safety and quality are the top priorities,” Toyota said of the latest disclosures.

The committee found irregularities during horsepower output testing for three engine models. In total, 10 vehicle models used the engines globally, including six in Japan, according to the company. The committee had initially been investigating Toyota Industries for certification issues related to engines used in forklifts.

Japan’s transport ministry will start an on-site inspection of the company on Tuesday.