Tundra 4WD V8-5.7L (3UR-FE) (2007)
Engine Control Module: Component Tests and General Diagnostics
ECM Power Source Circuit
DESCRIPTION
When the ignition switch is turned ON, the battery voltage is applied to the IGSW of the ECM. The output signal from the MREL terminal of the ECM
causes a current to flow to the coil, closing the contacts of the integration relay (EFI relay) and supplying power to either terminal +B or +B2 of the
ECM.
Wiring Diagram