SFI SYSTEM


  1. OPERATION


    1. In this vehicle, there are 2 types of fuel pump controls. The fuel pump is controlled to an optimum speed to match the engine operating conditions, and the fuel pump operation is stopped when the SRS airbags deploy.

    2. The ECM transmits a fuel pump operation request signal to the fuel pump control ECU that corresponds to the engine operating conditions. The fuel pump control ECU receives this request signal and controls the speed of the fuel pump in 3 stages. As a result, under light engine loads, fuel pump speed is kept low to reduce electric power loss.

    3. A fuel cut control is used to stop the fuel pump when any of the SRS airbags deploy. In this control, if an airbag deployment signal from the center airbag sensor assembly is detected by the ECM, the ECM will turn off the circuit opening relay. As a result, the power supply to the fuel pump control ECU is stopped, causing the fuel pump to stop operating. After the fuel cut control has been activated, turning the engine switch from off to on (IG) cancels the fuel cut control, and the engine can be restarted.

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    4. The fuel pump control ECU controls fuel pump speed by receiving a duty cycle signal (FPC terminal input) from the ECM, and control is performed in 3 stages.

    5. The fuel pump control ECU also detects failures in the input and output circuits at the fuel pump ECU and transmits the failure status to the ECM.

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