Fuel Pump, Fuel Pump Electronic Control Unit & Fuel Pump Switch (LX470)

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Lexus SC 430, 2003 Lexus RX 300, 2003 Lexus LX 470, 2003 Lexus LS 430, and 2003 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.

Fuel pump operating speed (low, medium or high) is controlled by operating condition of engine such as starting, idling, light load or heavy load. Engine Control Module (ECM) delivers an input signal from FPC terminal on ECM to FPC terminal on fuel pump Electronic Control Unit (ECU) in accordance with engine operating condition. Fuel pump ECU uses this input signal to determine how much voltage should be delivered to fuel pump for varying fuel pump operating speed. Fuel pump is located in fuel tank. Fuel pump ECU is located behind inner panel, just behind driver's side rear wheelwell. It may be necessary to remove rear seat back and seat cushion to access ECU.

Fuel pump switch is in circuit between FPC terminal on ECM and FPC terminal on fuel pump ECU. Fuel pump switch may also be referred to as fuel pump inertia switch or fuel pump control switch. If vehicle is involved in a collision, fuel pump switch will shut off fuel pump by opening this circuit, and not allowing any input signal to be delivered from ECM to fuel pump ECU. Fuel pump switch is located on driver's side, under front carpet, next to front console box. See Fig 1. Fuel pump switch contains a reset switch which has an OFF and ON position. See Fig 1. Continuity will exist between electrical terminals on fuel pump switch with reset switch in ON position, and no continuity in OFF position. Reset switch must be in ON position for fuel pump operation.

Fig 1: Locating Fuel Pump Switch & Identifying Reset Switch Positions (LX470)