Production of both the bZ4X and Solterra at Toyota’s Motomachi assembly plant has been suspended ever since as Toyota Motor Corp. raced to find a remedy for the problem.
The defect stemmed from not accounting for the high torque exerted on the wheels by the car’s all-electric drivetrain. The wheels are attached with hub bolts. But even in low mileage use, the wheels can come loose due to vigorous driving – such as turning sharply or braking aggressively.
The problem was exacerbated from the extra weight of the EV’s lithium ion battery pack.
Maeda said the original wheel surface was too rough with wide variances in processing quality.
The fix involves adding a washer to the hub bolts and improving friction of the wheel surface.
The approach will be applied to other EVs in Toyota’s production plan, Maeda said. That would include the Lexus RZ, an all-electric crossover slated to land Stateside in first half of 2023.
Maeda said it took Toyota so long to introduce the remedy because engineers needed to verify its effectiveness and safety under various conditions, including turning, braking and acceleration.
Maeda declined to say how much the recall would cost Toyota or how many units of bZ4X production were lost. He also added that the company had not broached the matter of compensating Subaru for the recall. Toyota owns a 20-per-cent stake in Subaru Corp.
Toyota said it received the first field report of a problem from Taiwan in late May, after a front left wheel separated from the vehicle. That was followed by two reports from the United States.
In the United States, Toyota in August offered 2023 bZ4X owners and lessees make-goods, including the option to sell back their vehicles. Toyota’s recall filing said there were potentially 258 bZ4X vehicles involved in the United States. It was unclear how many customers returned their vehicles.
The 2023 Subaru Solterra, which is being built by Toyota in Japan alongside the bZ4X, was also named in the June recall and stop-sale. Toyota’s initial U.S. recall filing said about 403 Solterras were affected. But no Solterras had yet been delivered to customers.
The bZ4X went on sale in the United States in late spring as Toyota's first EV since the RAV4 EV it built in cooperation with Tesla in 2014. Toyota wants to sell 3.5 million electric vehicles a year by 2030 across the Toyota and Lexus brands. Lexus will transform into an electric-only brand in Europe, the United States and China in 2030, when it plans to be prepared to sell 1 million EVs annually.
Following that, Lexus will offer nothing but full-electric vehicles worldwide by 2035.
The 2023 Toyota BZ4X arrived in Canadian dealerships this June, first in BC and Quebec, which qualify for provincial EV subsidies as well as federal EV incentives.
Still, investors and environmentalists have criticized Toyota for being slow in committing to EVs as it continues to tout gasoline-electric hybrids as a viably green alternative.
Greg Layson of Automotive News Canada contributed to this report.