DTC B1A10: Keyless/F.A.S.T. key 1 low battery; DTC B1A11: Keyless/F.A.S.T. key 2 low battery; DTC B1A12:/F.A.S.T. key 3 low battery; DTC B1A13: Keyless/F.A.S.T. key 4 low battery: 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:
When replacing the ECU, always check that the communication circuit is normal.