DTC P1566: Engine - ACC/FCM Control State Mismatch < ACC >: Notes
WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
If diagnostic trouble code No. P1566 is stored from ECM, surely perform CAN bus line diagnosis.
CAUTION:
Replace ECU after certainly confirming that the communication circuits are normal.