A supplier to the automaker said it had shut down its computer network to respond to what might have been a hack or a virus.
TOKYO — Toyota, the world’s largest automaker, said on Monday that it had suspended all production in Japan after a possible cyberattack at a major supplier.
The stoppage followed a problem with computer systems at Kojima Industries, a manufacturer of automotive components, that disrupted the company’s ordering systems. The problem first appeared Saturday night, and the company decided to shut down its computer network to prevent the issue from spreading to customers, a company spokesman said.
Kojima Industries has not yet been able to determine the cause of the problem, but it suspects a cyberattack or virus. The company’s website remained down Monday evening.
In comments at a news conference on the situation in Ukraine, Prime Minister Fumio Kishida of Japan said the government was aware of the Toyota shutdown and was investigating the cause.
Cyberattacks have become increasingly common in Japan in recent years. Japanese companies have been slow to update their networks to account for the growing use of ransomware by criminals, as well as intrusions by state actors. Manufacturers have been the most common targets for the attacks, which can essentially hold computer systems and valuable data hostage.
Like many other automakers, Toyota had to substantially cut production after the pandemic wreaked havoc on global supply chains and led to shortages of semiconductors and other components.
Last year, after the initial waves of the virus passed and global demand for automobiles surged, Toyota announced optimistic plans to produce 9.3 million units worldwide by March 31, the end of its fiscal year.
But skyrocketing demand for semiconductors and recurring waves of infection forced the company to reduce those plans first to nine million and then, in February, to eight and a half million.
Even before the problems at Kojima Industries, Toyota had planned temporary stoppages in March at several factories in Japan because of parts shortages.
The stoppage announced on Monday includes Toyota’s 14 domestic factories and will affect the production of 13,000 vehicles, a Toyota spokeswoman said, adding that the company could not yet say for certain how long the factories would remain idle.
Despite the setbacks, Toyota has managed to use lessons learned during a 2011 earthquake and tsunami that devastated northeastern Japan to adjust to the pandemic’s disruptions better than its competitors, topping the global auto sales charts for two consecutive years.
Hino, a subsidiary of Toyota that manufactures heavy trucks and buses, said in a statement Monday that it would also pause production at two factories because of problems at an unspecified supplier. Another subsidiary, Daihatsu, has also paused some production, according to local media reports.