Toyota Motor said it had halted the global shipments of 10 vehicles after it discovered that an affiliate had mishandled the testing of diesel engines used in the automobiles, the latest embarrassing problem to hit the world’s biggest automaker in recent months.
The Toyota affiliate used software to measure horsepower output that made “values appear smoother with less variation,” Toyota, the parent company, said in a statement on Monday. The vehicles “meet engine output standards,” and there is no need to stop using the engines or vehicles, the company said.
Still, Toyota decided to stop shipping the 10 models that use three diesel engines at issue. Among the models that will temporarily be shut down are the popular Hilux pickup truck and the Land Cruiser 300 sport utility vehicle. Toyota did not say how many vehicles were affected.
Japan’s transportation ministry said in a statement that it had ordered Toyota Industries to address its mismanagement of the engine testing, adding that it would conduct inspections and issue penalties.
“Fraud is an act that undermines user confidence and shakes the very foundation of the automobile certification system,” the ministry said.
At a news conference, Koichi Ito, the chief executive of Toyota Industries, apologized for the mishaps. “We are extremely sorry that this was caused by Toyota Industries Corporation,” he said. “The cause for the problem was our company system structure.”
Koji Sato, the chief executive of Toyota Motor, said the problem affected the production of about 43,000 diesel engines a month.
In December, Toyota was rocked by a series of recalls and production shutdowns. First, it recalled about one million vehicles in the United States because of an issue with airbags. Then, it reported that Japan’s government was investigating Daihatsu, the subsidiary, for safety problems that dated back decades.
Daihatsu said it would stop shipments of all of its models because of the safety-inspection irregularities. Last week, it said it was recalling 320,000 Daihatsu vehicles and was still not ready to reopen its production facilities.
Toyota said it understood “the gravity” of the two back-to-back testing problems that “have shaken the very foundations of the company as an automobile manufacturer.”
Japanese auto companies are facing their biggest business challenge since becoming global giants in the 1980s. Toyota, which in the 1970s became the leader in automotive manufacturing efficiency, has failed to keep up with changing consumer preferences and a push by governments around the world to greatly reduce the burning of fossil fuels, the main cause of climate change. Last year China supplanted Japan as the world’s largest exporter of cars.