Toyota said Tuesday it has been hit by a technical glitch forcing it to suspend production at all of its 14 factories in Japan.
The world's biggest automaker gave no further details on the stoppage, which began Tuesday morning, but said it did not appear to be caused by a cyberattack.
The company said the glitch prevented its system from processing orders for parts, resulting in a suspension of a dozen factories or 25 production lines on Tuesday morning.
The company later decided to halt the afternoon shift of the two other operational factories, suspending all of Toyota's domestic plants, or 28 production lines.
"We do not believe the problem was caused by a cyberattack," the company said in a statement to AFP.
"We will continue to investigate the cause and to restore the system as soon as possible."
The incident affected only Japanese factories, Toyota said.
It was not immediately clear exactly when normal production might resume.
The news briefly sent Toyota's stocks into the red in the morning session before recovering.
Last year, Toyota had to suspend all of its domestic factories after a subsidiary was hit by a cyberattack.
The company is one of the biggest in Japan, and its production activities have an outsized impact on the country's economy.
Toyota is famous for its "just-in-time" production system of providing only small deliveries of necessary parts and other items at various steps of the assembly process.
This practice minimises costs while improving efficiency and is studied by other manufacturers and at business schools around the world, but also comes with risks.
The auto titan retained its global top-selling auto crown for the third year in a row in 2022, and aims to earn an annual net profit of 2.58 trillion yen ($17.6 billion) this fiscal year.
Major automakers are enjoying a robust surge of global demand after the Covid-19 pandemic slowed manufacturing activities.
Severe shortages of semiconductors had limited production capacity for a host of goods ranging from cars to smartphones.
Toyota has said chip supplies were improving and that it had raised product prices, while it worked with suppliers to bring production back to normal.
However, the company was still experiencing delays in the deliveries of new vehicles to customers, it added.
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