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.
Pressure Sensor
The solenoid valve is temporarily activated by ECU whenever ignition switch is turned to "ON" or "START" positions. When activated, the solenoid measures ambient barometric pressure from above throttle valve. Ambient barometric pressure changes due to weather and/or altitude. This information is sent to ECU for controlling fuel delivery time. See Fig 1 .
After a predetermined period of time, solenoid valve is deactivated by ECU and solenoid measures intake manifold pressure below throttle valve. The ECU compares barometric pressure to intake manifold pressure and an absolute value is used to determine fuel delivery and ignition timing.
The pressure sensor and solenoid valve are also used for altitude compensation. These components inform ECU of altitude. The ECU calculates air/fuel ratio necessary for engine operation in high altitude areas.
Use the Manual With the Right Hardware
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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.
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