A maker of tiny Japanese pickup trucks shut down its factories after admitting it forged safety tests for 30 years

• Daihatsu has halted production after a report found forged vehicle safety tests dating back to 1989.
• The Toyota subsidiary is best known for its tiny "kei cars" which are popular in Japan.
• Toyota plans to shake up Daihatsu in response to the scandal, saying it needs "fundamental reform."

A Japanese tiny-car manufacturer has halted production of its vehicles after admitting it had been forging safety tests for 30 years.

Toyota subsidiary Daihatsu, known for its miniature vehicles, halted factory operations on Tuesday after a report found that it had been forging the results of some safety tests since 1989.

The company had already paused shipments of all its vehicles, and will now shut down its four Japanese factories until at least the end of January.

It's the latest development in a long-running saga surrounding the company's safety record, with Daihatsu first acknowledging it had falsified some crash tests in April.

An internal report into the issues, released on December 20, found 174 cases in which the company manipulated data or made adjustments to its vehicles to get them past safety tests.

The vehicles impacted included those sold under the Toyota brand. Daihatsu found that doors on some of its vehicles could become difficult to open from the outside in a crash, although it said it was not aware of any related accidents.

The report also said that while there was an increase in the number of falsified cases after 2014, the oldest incident dated back to the late 1980s.

Daihatsu is best known for making "kei" cars and trucks, tiny vehicles that are hugely popular in Japan, and have even taken off among some drivers in the US.

The company's kei vehicles include the Hijet truck, which has been a bestseller in Japan since the 1960s, and the 7-foot Copen roadster, which features a convertible folding roof.

Daihatsu has apologized for the safety irregularities and vowed to "make company-wide efforts to regain the trust of our stakeholders," with CEO Soichiro Okudaira saying the automaker had "betrayed the trust of our customers" in comments reported by the Guardian.

Toyota, which acquired Daihatsu in 2016, has also promised to overhaul Daihatsu in response to the findings, saying that the subsidiary needs "fundamental reform."

The ongoing scandal is a headache the Japanese auto giant, which is grappling with its own safety issues, could do without.

On the same day that Daihatsu released its report, Toyota was forced to recall 1 million cars in the US over fears that some passenger airbags may fail to deploy in an accident.

Toyota did not immediately respond to a request for comment from Business Insider, made outside normal working hours. Daihatsu could not be reached for comment.