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.
Circuit Description
The main relay, is controlled by Powertrain Control Module (PCM). PCM provides a ground for relay coil anytime ignition is on. Main relay supplies ignition positive voltage to many engine control systems and components. The following components receive power from main relay:
- Fuel Pump Relay
- Fuel Injectors
- Mass Air Flow (MAF) Sensor
- Evaporative (EVAP) Emission Control System Solenoids
- Exhaust Gas Recirculation (EGR) Valve
- Idle Air Control (IAC) Valve
- Powertrain Control Module (PCM)
NO RELATED
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.