The present invention relates to a method for testing or verifying an indirect pressure monitoring system for a wheel of a vehicle, comprising the steps of: checking an inflation pressure of at leasttwo wheels of the vehicle, if the at least two wheels are deflated, The at least two wheels are inflated to a predetermined pressure; controlling advancement of the vehicle to bring the at least two wheels to or above the drag rotating device; activating the drag rotating device to simultaneously move the at least two wheels Drag to rotate at a different speed relative to the other; verify that the indirect pressure monitoring system issues an abnormal signal, such as a difference in rotational speed or pressure between the at least two wheels that are dragged and rotated, if indirect pressuremonitoring If the system does not send an abnormal signal, the indirect pressure monitoring system is not working properly and must be repaired. The invention also relates to a unit of an indirect pressure monitoring system for testing or verifying the wheels of a vehicle.