DTC B261A: Push-Button Ignition Switch: Description
WARNING: This page is about a different car, the 2016 Infiniti QX50. However, it is still accessible from the selected car via links, so may be relevant.
BCM transmits the change in the power supply position with the push-button ignition switch to IPDM E/R via the CAN communication. IPDM E/R transmits the power supply position status via CAN communication to BCM.