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Home >> Toyota >> 1989 >> Celica L4-2.0L (3S-FE) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Main Relay (Computer/Fuel System) >> Description and Operation >> ECU Power Supply
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ECU Power Supply


Battery voltage is supplied to the BATT terminal of the ECU at all times. The Electronic Fuel Injection Main Relay provides voltage to terminals +B and +B1 of the ECU when the ignition switch is turned on. The EFI fuse (15A) supplies continuous battery voltage to the EFI Main Relay. System battery voltage must be at least 10 volts in order to operate EFI and ECU functions.

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