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
When ignition switch is turned on, 9-14 volts is applied to terminal IGSW at ECM. EFI relay control circuit in ECM then sends a signal to terminal MREL at ECM to switch EFI relay on. This signal causes current to flow to coil, closing contacts of EFI relay and supplying power to terminal +B of ECM. If ignition switch is turned off, ECM continues to switch on EFI relay for a maximum of 2 seconds for initial setting of throttle valve.
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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.