Five transport ministry bureaucrats started reviewing materials and conducting interviews at the headquarters of Toyota in Aichi Prefecture on Tuesday after the carmaker admitted this week to vehicle-testing wrongdoings.

The low-key morning raid came as questions started to emerge about whether the infractions being investigated are meaningful and whether the regulations that were broken are properly formulated and enforced.

Questions are also being asked about the implications of complex and often hard-to-understand standards at a time when Japan’s automakers face intense challenges globally.