2008 Lexus RX 400h FWDFACTORY OEM SERVICE PROCEDURE

Fuel Pump Control Circuit: Description

The fuel pump is operated by the engine control system according to the vehicle running condition. After the engine control system receives the engine start requirement signal from the HV control system, an NE signal comes in immediately when the engine is cranked by MG1 (basically, the fuel pump can operate while the NE signal is generated).

The engine control system grounds the FC terminal line after receiving an NE signal. It causes to energize the coil in the circuit opening relay, and the current flows to the fuel pump.

When the signal to stop the engine comes from the HV control system to the engine control system, or when the fuel cut operation is performed such as decelerating by the engine brake, the fuel pump is stopped.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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