N182206730 - Customer Satisfaction Program. Certain vehicles equipped with special service package (RPO 5W4) and certain 2015 ? 2019 Chevrolet Tahoe vehicles equipped with police package (RPO 9C1) or special service package (RPO 5W4) may have a condition in which frequent, repeated brake applications at low speed or idle speeds can deplete available brake vacuum assist faster than vacuum can be replenished by the system, which can lead to increased brake pedal effort, hard brake pedal and potentially increased stopping distance. These vehicles utilize Hydraulic Brake Boost Assist to supply additional hydraulic pressure when the vacuum boost is not sufficient to achieve the driver?s intended brake force. Dealers will reprogram the Electronic Brake Control Module in these vehicles with a new calibration that will improve how the system utilizes the Hydraulic Brake Boost Assist function when vacuum assist is depleted.