A method of calibrating a hydraulically operated park brake of a continuously variable transmission of a vehicle. With the vehicle moving at a set, slow speed within a specified range, and the park brake off, a search technique is used, wherein the brake hydraulic pressure is reduced by application of a control signal of a selected test value to apply the brake. When the selected test value is reached, it is held constant, and a condition in a HSU of the transmission is monitored for a change indicative of engagement of the park brake. This will expectedly be in the form of a pressure change and more particularly an increase indicating initial contact between the plates of the brake, and if the HSU change is not detected, the step will time out and another control signal value will be tested.