Toyota Tundra Service Manual: Parts Location

IG Power Source Circuit

Precaution

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Toyota Tundra Service Manual > Sfi System: ECM Power Source Circuit
DESCRIPTION When the ignition switch is turned to ON, the battery voltage is applied to the IGSW terminal 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 terminals + ...