Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
System Description
Low fuel pressure control
- The low fuel pressure pump is controlled by the fuel pump control module (FPCM) and pumps fuel according to a driving condition. The pumped fuel passes through the fuel filter and is sent to the high pressure fuel pump. FPCM controls the low pressure fuel pump, according to a signal from ECM as shown in the table below.
Conditions Amount of fuel flow Supplied voltage After a laps of 1 second after ignition ON OFF 0 V - For 1 second after ignition ON (engine coolant temperature is 5°C (41°F) or less, or 40°C (104°F) or more)
- For 1 second after turning ignition switch ON
- Engine is running under low load and low speed conditions
Low Approximately 8.5 V - For 1 second after ignition ON (engine coolant temperature is 5°C (41°F) or more, or 40°C (104°F) or less)
- Engine cranking
- Engine coolant temperature is below 10°C (50°F)
- Engine is running under high load and high speed conditions
High Battery voltage (11 - 14 V) Except the above Mid Approximately 10 V - Low fuel pressure is adjusted by the fuel pressure regulator.
High fuel pressure control
The high pressure fuel pump raises the pressure of the fuel sent from the low pressure fuel pump. Actuated by the camshaft, the high pressure fuel pump activates the high pressure fuel pump solenoid based on a signal received from ECM, and adjusts the amount of discharge by changing the timing of closing the inlet check valve to control fuel rail pressure.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.