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NHTSA safety investigation

NHTSA Investigation PE25015

Preliminary Evaluation · Honda (American Honda Motor Co.) · SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:MASTER CYLINDER

ClosedPreliminary Evaluation

An investigation is not a finding that a defect exists.

NHTSA opens an investigation to examine whether a safety defect may exist. An open investigation is not a determination that a defect exists, and many investigations close without a recall. Investigations can, however, lead to one.

Model years namedModel years in our database that NHTSA associated with this inquiry. Being named in an investigation says nothing about whether an individual vehicle has any problem.
2
1 model
Opened
Oct 23, 2025
Preliminary Evaluation
Closed
May 21, 2026
No associated recall recorded

What NHTSA is examining

The agency's own description of the inquiry, quoted as published

Loss of braking force

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.

An investigation is a separate record from a recall and from a manufacturer communication. A manufacturer campaign to repair a safety defect or a failure to meet a federal safety standard.

Investigation details

Identifiers, dates and outcome as recorded by NHTSA

Action number
PE25015
Investigation type
Preliminary Evaluation (PE)
Status
Closed
Manufacturer
Honda (American Honda Motor Co.)
Component
SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:MASTER CYLINDER
Opened
Oct 23, 2025
Closed
May 21, 2026
Associated recall campaign
None recorded

Vehicles named in this investigation

2 model years across 1 model

Being named here means NHTSA included the vehicle in the scope of its inquiry. It is not a statement that these vehicles have a defect.