General Motors will be contacting the owners of certain 2014-2018 Cadillac, Chevrolet and GMC trucks and SUVs, because of a problem with the braking system. The vehicles affected include:
According to the defect report, these vehicles were manufactured with a vacuum brake assist pump design that is prone to accumulate debris and restrict the flow of oil to the pump. If the oil pressure drops, drivers may feel a vibration in the brake pedal, increased braking effort and longer stopping distances. A “Service brake assist” warning will activate 2-5 minutes after the vacuum level drops, and a Diagnostic Trouble Code (DTC) will be set. These vehicles are equipped with a secondary, hydraulic power brake assist system that activates to provide power brake assist when the vacuum drops, but it is limited at lower speeds.
Dealers will correct the problem by reprogramming the Electronic Brake Control Module with a new calibration that will improve how the system uses the hydraulic brake boost assist function when the vacuum assist is depleted. Owners are encouraged to follow the oil change intervals recommended by the manufactured, as failure to do so could contribute to the condition.