According to this article:
https://news.yahoo.co.jp/expert/articles/8a8ee1190b305bc4a52...The main issues are thought to be
Tampering with airbag timer ignition
Falsely recording test results
Falsification of test speeds
Falsely recording tire pressure
Replacing the acceleration data of the upper portion of passenger seat
The article goes into more depth re each item, DeepL is your friend if you don't read Japanese
