DTC P0688-1F: ECM/PCM Power Relay Sense Circuit Intermittent [04/2020 - 09/2022]: Wiring Diagram

WARNING: This page is about a different car, the 2022 Toyota Corolla, 2021 Toyota Corolla, and 2020 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.