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Home >> Lexus >> 1999 >> SC 300 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Computerized Engine Controls >> ECM Power Source Circuit (Ignition Keyed) >> Circuit Description
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Circuit Description

When ignition switch is turned on, 9-14 volts is applied to the terminal IGSW at ECM main relay control circuit, sending a signal to terminal M-REL at ECM switching EFI main relay on.