The National Highway Traffic Safety Administration has officially opened a defect petition investigation into over 137,000 Acura vehicles following alarming reports of sudden all-wheel-drive failures. The Office of Defects Investigation formally launched the probe on March 6, 2026, targeting specific late-model luxury vehicles manufactured by American Honda Motor Co.
Which Acura Models Are Affected?
According to the official ODI resume, the estimated population of affected vehicles sits at a substantial 137,329 cars. The investigation strictly covers two of the brand’s most popular nameplates: the 2021 through 2023 model year Acura TLX sedans, as well as the larger 2022 through 2023 model year Acura MDX SUVs.
According to the reports published by the NHTSA, a severe mechanical breakdown within the vehicle’s drivetrain is to blame. Specifically, the defect involves the interfacing splines connecting the transmission to the rear-wheel-drive power take-off unit, which are physically failing.
When these critical splines fail, the mechanical link is severed, completely preventing the transfer of drive power to the rear axle. As a result, the vehicle’s advanced all-wheel-drive system unusable, instantly converting the vehicle into front-wheel-drive-only. Beyond the obvious loss of advertised AWD performance, the petition alleges that this sudden loss of rear-wheel power results in a dangerous reduction of vehicle directional control for the driver.
This federal investigation was prompted by a defect petition originally submitted to the ODI earlier this year on January 9, 2026. To back up the claims of widespread drivetrain failure, the petitioner collected and cited 48 separate complaints previously received by the ODI that allege this exact same mechanical issue.
Currently, the investigation remains in the defect petition phase. The NHTSA is actively evaluating these 48 consumer complaints to conduct a thorough technical review under 49 CFR Part 552. Once the safety agency determines if these complaints are directly related to the alleged spline failure, they will officially decide whether to grant or deny the petition.
If the petition is granted, this preliminary investigation could rapidly escalate into a massive, mandatory safety recall for Honda’s luxury division.
