DTC C1437: Lost Communication with ECM: Wiring Diagram
WARNING: This page is about a different car, the 2009 Lexus IS 350 and 2009 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
Refer to DTCs U0073, U0100, U0123, U0124 and U0126. Refer to WIRING DIAGRAM .