Some owners of 2016 Buick Lacrosse or Regal vehicles may comment on a hard brake pedal on a cold start-up and/or a service brake assist message. Upon diagnosis, you may find DTCs C027B or P050F set in the EBCM.
On some vehicles, the connector at the KR14 brake booster pump motor relay was not fully seated. Inspect the KR14 connector.
The brake booster pump relay is incorporated into the brake booster pump motor. If the connector is not fully seated, press the connector fully into the cavity. After seating the connector, deplete brake booster vacuum by depressing the brake pedal several times with the engine off. Then restart the engine and confirm that the brake booster pump runs and there is normal function of the brake pedal.
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Information for Technical Service Bulletins comes from ProDemand, Mitchell 1's auto repair information software for domestic and import vehicles. Headquartered in San Diego, Mitchell 1 has provided quality repair information solutions to the automotive industry since 1918.
