Sensor | Input signal to ECM | ECM Function | Actuator
Crankshaft position sensor (POS) Camshaft position sensor (PHASE) | Engine speed | Fuel pump control | Sub fuel pump relay ↓ Sub fuel pump
Mass air flow sensor | Amount of intake air

The sub fuel pump (1) is installed on the main fuel level sensor unit, fuel filter and fuel pump assembly (2) in line with the fuel pump (3). The ECM activates the sub fuel pump for covering the fuel supply in high engine speed and high load areas. The ECM does not activate the sub fuel pump directly. The ECM controls the fuel pump by turning the sub fuel pump relay ON/OFF.