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.
Fuel Injector Control Module (FICM)
The FICM requires a 12-volt power source. The FICM receives power from the vehicle batteries through the FICM relay contacts each time the key is turned to the ON position. As the key is turned to the ON position, the FICM provides an internal ground to the coil side of the FICM relay. This closes the relay contacts and provides the FICM with the necessary power. The PCM communicates with the FICM using the CAN protocol. The CAN protocol is an international standards organization (ISO) standard for serial data communication. The CAN protocol standard includes a physical layer using differential transmission on a twisted pair of wires and a data link layer that defines different message types, arbitration rules for bus access, methods for concern detection and concern confinement. The FICM receives information from the PCM, including the volume of fuel desired, RPM, engine oil temperature, injection control pressure, and others. The FICM uses those signals to calculate fuel injection and duration. After calculating injector fuel delivery time, the FICM sends 48 volts at a 20-amp pulse to the correct injector so that the correct amount of fuel is delivered to the cylinder at the correct time.
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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.