According to the study, overall vehicle dependability has improved year over year, as the number of defects and malfunctions have decreased. That said, more problems were attributed to the ACEN or Audio/Communication/Entertainment/Navigation category with more owners complaining about user-friendliness and ease-of-use (or lack thereof).

The study, now in its sixth year, measures problems experienced by original owners of vehicles after 37 to 54 months of ownership. It is based on 19,488 responses fielded in June to July of this year.

The study examines 177 problem symptoms across eight categories: vehicle exterior; driving experience; features/controls/displays (FCD); audio/communication/entertainment/navigation (ACEN); seats; heating, ventilation and air conditioning (HVAC); vehicle interior; and engine/ transmission. Overall dependability is determined by the number of problems reported per 100 vehicles (PP100), with a lower score reflecting higher quality.

Among the 14 brands in this year’s study, dependability improves by at least 10 points for 7 out of 14 brands, with the number of reported problems decreasing for 12 out of the 14 brands. Highest ranked is Daihatsu with a 54 PP100, beating Lexus and Toyota by one point (55 PP100). Mazda is the worst ranked Japanese brand, though on a brighter note, their dependability has shot up by 24 points compared to 2019 (81 PP100).

J.D. Power says that the largest improvement for Japanese automakers is in the engine/transmission category (-2.4 PP100), specifically for automatic engine shut down/restart/re-engagement problems (-0.6 PP100), and automatic transmission–hesitation/shifts at wrong times (-0.4 PP100). Vehicle dependability also notably improves in the vehicle exterior (-1.9 PP100) and the vehicle interior (-1.8 PP100) categories.

Moreover, J.D. Power says that brand loyalty hinges on dependability. Nearly one-third (30 percent) of owners indicate with a rating of 9 or 10 points that they “definitely will” purchase the same brand again. In the 2020 Japan Initial Quality Study published in August, 26 percent of owners say the same after two to nine months of ownership. This suggests that, if brands can satisfy their customers in terms of initial quality, they can expect to maintain high dependability ratings and brand loyalty even after a longer period of ownership.