Ignition System: Description and Operation

IGNITION SYSTEM

GENERAL DESCRIPTION

[2.4L ENGINE]
This system is provided with four ignition coils with built-in ignition power transistors for each of the cylinders.
Interruption of the primary current flowing in the primary side of ignition coil generates a high voltage in the secondary side of ignition coil.
The engine control module (ECM) or powertrain control module (PCM) controls the four ignition power transistors to turn them alternately ON and OFF. This causes the primary currents in the ignition coils to be alternately interrupted and allowed to flow to fire the cylinders in the order 1-3-4-2.

The ECM or PCM determines which ignition coil should be controlled by means of the signals from the camshaft position sensor which is incorporated in the camshaft and from the crankshaft position sensor which is incorporated in the crankshaft.
It also detects the crankshaft position to provide ignition at the most appropriate timing in response to the engine operation conditions.
When the engine is cold or operated at high altitudes, the ignition timing is slightly advanced to provide optimum performance.