Denial of Motor Vehicle Defect Petition
This notice sets forth the reasons for the denial of a petition, DP26-001, submitted by Mr. Christopher Mammarella (the Petitioner) to the Administrator of NHTSA (the "Agency") by a letter dated January 9, 2026, under 49 U.S.C. 30162 and 49 CFR part 552. The Petitioner requests the Agency initiate a safety defect investigation into allegations of a mechanical failure that results in the loss of All Wheel Drive (AWD) in certain Model Year (MY) 2021 to 2023 Acura TLX and MY 2022 to 2023 Acura MDX vehicles (the "Subject Vehicles") equipped with Acura's Super Handling All Wheel Drive (SH-AWD). As a result of the failure, these vehicles permanently lose the ability to transfer drive torque to the rear wheels effectively making them front wheel drive only. NHTSA's Office of Defects Investigation (ODI) has determined that the issues raised in the Petition are not likely to result in a finding that a defect related to motor vehicle safety exists. This determination is based on a technical review by ODI of available information, which included: (1) consumer complaints submitted by the petitioner; (2) consumer complaint information in the agency's databases; and (3) other relevant information in possession of the agency. As a result, further investigation of the issue raised by the Petition is not warranted and the Agency, accordingly, has denied the Petition.
What this item does
The short version, using the agency's own summary text.
This notice sets forth the reasons for the denial of a petition, DP26-001, submitted by Mr. Christopher Mammarella (the Petitioner) to the Administrator of NHTSA (the "Agency") by a letter dated January 9, 2026, under 49 U.S.C. 30162 and 49 CFR part 552. The Petitioner requests the Agency initiate a safety defect investigation into allegations of a mechanical failure that results in the loss of All Wheel Drive (AWD) in certain Model Year (MY) 2021 to 2023 Acura TLX and MY 2022 to 2023 Acura MDX vehicles (the "Subject Vehicles") equipped with Acura's Super Handling All Wheel Drive (SH-AWD). As a result of the failure, these vehicles permanently lose the ability to transfer drive torque to the rear wheels effectively making them front wheel drive only. NHTSA's Office of Defects Investigation (ODI) has determined that the issues raised in the Petition are not likely to result in a finding that a defect related to motor vehicle safety exists. This determination is based on a technical review by ODI of available information, which included: (1) consumer complaints submitted by the petitioner; (2) consumer complaint information in the agency's databases; and (3) other relevant information in possession of the agency. As a result, further investigation of the issue raised by the Petition is not warranted and the Agency, accordingly, has denied the Petition.
Denial of a petition to open a defect investigation.
Important dates
The dates that matter most for this item.
Published
August 6, 2026