The Toyota Tercel fuel pump electronic components consists of: battery, IG switch, EFI main relay, circuit opening relay, fuel pump, ECM, starter relay and starter. The diagram below shows the the Toyota Tercel Fuel Pump Control Circuit.
When the engine is cranked, current flows from terminal ST of the ignition switch to the starter relay coil and also current flows to terminal STA of ECM (STA signal). When the STA signal and NE signal are input to the TCM, Tr is turned ON, current flows to coil of the circuit opening relay, the relay switches ON, power is supplied to the fuel pump and the fuel pump operates. While the NE signals is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the fuel pump also keeps operating.
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