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.
Coil On Plug (COP)
The COPs are part of the distributorless ignition system. They are the source of the high voltage which is used to generate the spark by the spark plug. The hybrid vehicle uses four COPs, one for each cylinder. The COPs are mounted directly onto the spark plugs. The function of the COP is to convert low voltage into high voltage in excess of 40,000 volts.
The COP consists of primary and secondary windings. The primary winding is energized by the IGN START/RUN circuit. The PCM coil driver circuit is connected to the primary winding as well. The secondary winding is connected to the spark plug. The current flowing through the primary winding generates the magnetic field across both windings. The PCM activates the coil driver circuit by opening it. The instant the circuit opens the magnetic field collapses, inducing current flow in the secondary winding.
The COP has three different modes of operation: engine crank, engine running, and CMP failure mode effects management (FMEM).
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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.