Toyota Motor has admitted it improperly obtained vehicle certifications for seven car models by carrying out safety tests “using methods that differed from the government standards”, as part of an ongoing investigation by Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT).

Toyota said, of the seven models, four had been discontinued including the Crown, Isis, Sienta and RX.

For those, the automaker admitted “errors occurred in crash tests and other test methods”.

For the three models currently in production in Japan, the Corolla Fielder, Corolla Axio and Yaris Cross, certification was obtained “using inadequate data in pedestrian and occupant protection tests”.

The automaker said: “We sincerely apologise for any concern or inconvenience this may cause to our customers and stakeholders who have placed their trust in Toyota”, while acknowledging more certification issues had been discovered at its Hino Motors, Daihatsu Motor and Toyota Industries subsidiaries.

Toyota said, following a comprehensive internal investigation, it could “confirm there are no performance issues that contravene laws and regulations. Therefore, there is no need to stop using the affected vehicles”.

The company said it had decided to temporarily halt shipments and sales of the three models currently in production, effective immediately, while continuing to provide detailed explanations to the authorities and expedite appropriate measures, including conducting testing in the presence of witnesses.

According to local reports, the MLIT said other domestic automakers had also declared similar instances of misconduct – Honda, Mazda, Suzuki and motorcycle manufacturer Yamaha.

The ministry said it would conduct on site inspections at the offices of these automakers before deciding on administrative action.