A small number of 2021 Ford F-150 trucks could experience an electronic brake booster leak. The leak could result in brake fluid entering the electronic control unit (ECU), causing longer break pedal travel, higher pedal effort and reduced braking.

In May 2021, Ford’s Critical Concern Review Group reviewed three F-150 truck warranty claims where brake fluid from the electronic brake booster leaked into the ECU. Ford’s review of supplier records found that the supplier had identified 169 2021 model year F-150 brake booster assemblies in December 2020 because they were potentially assembled with a broken clinching tool, used to secure the pressure sensor to the booster housing. Further review of supplier and Ford records determined that 51 of the 169 quarantined parts were inadvertently shipped to Ford’s Dearborn Truck Plant and assembled into vehicles, all of which were shipped to dealers in the U.S.

Engineering analysis found that a brake booster with an incomplete clinch between the pressure sensor and the brake booster housing can cause brake fluid to leak through the pressure sensor into the ECU. This can reduce braking effectiveness of the brake circuits.

Those receiving notifications will be asked to return to their dealerships to have the ECU replaced. Ford’s number for this recall is 21S33 and the NHTSA campaign number is 21V-533.