Fuel Pump Control Circuit
CIRCUIT DESCRIPTIONWhen starting the engine with ignition switch:
HV ECU receives ST signal and decides to start the engine, and send the signal of the engine start prior signal to the ECM by the communication between the ECM and HV ECU.
ECM receives that signal and turns ON the circuit opening relay slightly earlier, then turns the fuel pump.
When starting the engine in an intermittent operation:
With the cranking by MG1, NE signal comes in immediately, so the ECM receives the generation of NE signal and turns the fuel pump. (At this time, no reference of the communication from HV ECU)
When stopping the fuel pump:
When the signal to stop the engine comes in to the ECM from HV ECU from HV ECU side, the fuel pump stops.
At the time of the fuel cut operation such as deceleration by the engine brake, the fuel pump stops.
Wiring Diagram:
INSPECTION PROCEDURE
Step 1 - 4:
Step 4(continued) - 6:
TOYOTA hand-held tester:
Step 1 - 3:
Step 4 - 6:
OBD II scan tool (excluding TOYOTA hand-held tester):