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.
Computer Controlled Coil Ignition (C(3)I)
The C(3)I system is used on 3.0L & 3.8L Turbo models with Sequential Fuel Injection. It consists of the ECM, ignition module, camshaft sensor, crankshaft sensor and connecting wires. This system uses a sealed 14 pin connector which goes directly to the ECM.
Each cylinder is paired with the cylinder opposite it in the firing order. These pairs are; 1-4, 5-2 and 6-3. Both cylinders are fired at the same time; the cylinder on compression and the cylinder on exhaust. The cylinder on exhaust requires little available voltage to arc. The remaining voltage is used by the cylinder on compression. There are 3 coils for a 6-cylinder engine. Spark distribution is timed by a signal from a Hall Effect crankshaft sensor. This signal is used by the ignition module to trigger each cylinder at the proper time.
The system also uses a Hall Effect camshaft sensor. This sensor provides the ECM with a voltage signal when the number 1 cylinder is on the compression stroke. This information is used to properly time the fuel injection and spark.
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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