Toyota promised Friday to strengthen oversight of its vehicle certification so the scandal that surfaced recently over improper tests will never recur.

Japan’s top automaker outlined in detail the measures it will take, including greater managerial involvement, assigning more staff to certification tasks and clarifying responsibilities of specific posts, such as the chief engineer.

The report was presented to the Japanese government, which reprimanded Toyota last month.

Two months ago, Toyota Motor Corp. acknowledged wide-ranging fraudulent testing, including the use of inadequate or outdated data in crash tests, incorrect testing of airbag inflation and engine power checks.

The wrongdoing does not affect the safety of the vehicles already on roads, which include the popular Corolla subcompact and Lexus luxury vehicles, so owners don’t have to do anything.

But it has been a major embarrassment for a manufacturer that prides itself on empowering its workers to ensure quality control.

Toyota has suspended production of some models. Japanese media reports have speculated the scandal will lower Toyota’s annual global output by some 500,000 vehicles. Toyota sells 11 million vehicles a year worldwide.

After the initial disclosure, Toyota found more cheating, including on certifications for pedestrian protection, side collisions and steering impact.

“There were many areas for improvement in the foundation of certification operation, such as the data management system and the establishment of regulations and procedures for the certification operations,” Toyota said in a statement.

A Japanese government investigation into Toyota began in January. The issue does not affect overseas production.

Similar fraudulent tests were found at Japanese automakers, Mazda Motor Corp. and Honda Motor Co., and at Toyota group makers Hino Motors and Daihatsu Motor Co.