General Motors is conducting a new safety campaign, in coordination with the National Highway Traffic Safety Administration (NHTSA), for 3,456,111 vehicles.

Out of those, the automotive giant estimates that 2 percent is suffering from a braking issue that could increase the stopping distance, leading to a higher crash risk.

“In some circumstances, these vehicles may have a condition in which the engine-mounted mechanical vacuum pump output may decrease over time, decreasing the amount of vacuum/power brake assist”, the NHTSA explained in its report.

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Should this happen, drivers will feel a vibration in the brake pedal or a change in the amount of pressure needed to depress it. Occupants will also hear a ticking noise coming from the engine compartment. Two to five minutes later, the ‘Service Brake Assist’ alert will activate and the software will then display a diagnostic trouble code.

Suffering from this condition are certain 2015-2017 Cadillac Escalades, 2014-2018 Chevrolet Silverados and GMC Sierras, and 2015-2018 Chevrolet Suburbans, Tahoes and GMC Yukons.

Subsequent to scheduling an appointment with an authorized GM dealer, technicians will thoroughly inspect each vehicle and reprogram the Electronic Brake Control Module with a new calibration that improves how the system uses the hydraulic brake boost assist when the vacuum assist is depleted.

GM will not reimburse owners, because a remedy was not available prior to the recall. The company has also not provided a notification schedule yet.