On October 23, 2025, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE25015 after receiving complaints concerning a loss of brake assist in 2019-2020 MY Acura ILX vehicles. These complainants alleged master cylinder failures resulting in soft pedal feel or the brake pedal intermittently going to the floor. These failures could result in extended braking distance increasing the risk of a crash. Honda found that residual plasticizer in the brake reservoir hose could contaminate the brake fluid. This contaminated brake fluid was then absorbed by the secondary cup seal, causing it to swell. Engine heat during operation could further expand the swollen seal, allowing brake fluid to pass. Brake fluid bypassing the master cylinder cup seals can reduce brake-pedal firmness and increase stopping distance. On April 08, 2026, Honda filed Recall 25V-859, recalling all 2016-2020 MY Acura ILX vehicles produced from October 9, 2014, to January 29, 2020. Under the recall, the dealer will replace the brake master cylinder with redesigned inner cup seals made of a different material, providing improved sealing capability. In view of Honda filing Recall 25V-859 addressing the subject of this investigation, ODI is closing this Preliminary Evaluation. NHTSA reserves the right to take additional action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.
