Faulty Ignition Coil 7
Ignition Coil 7 harness is open or shorted
Ignition Coil 7 circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
Engine may be running rough
The current flow, or dwell, through the primary ignition coil is controlled by the Powertrain Control Module (PCM) by providing a switched ground path through the ignition coil driver to ground. When the ignition coil driver is switched on, current rapidly builds up to a maximum value, determined by the coil inductance and resistance. When the current is switched off, the magnetic field collapses which induces a secondary high voltage surge and the spark plug is fired. This high voltage surge creates a flyback voltage which the PCM uses as a feedback during the ignition diagnostics. The PCM continuously monitors the ignition system for concerns. The P2318 code sets when the PCM detects a short to voltage in the circuit.