In 2007 Ishikawa Harima Industries (IHI) experienced large profit overstatements (and subsequent downward revisions) caused by overly-optimistic estimates used in percentage-of-completion accounting for large projects. At the bottom of the link below, you can see IHI’s explanation of the incident, and the actions it took for years afterwards in order to improve its internal controls and accounting:
http://www.ihi.co.jp/csr/english/2011/management/governance.html