Ignition System: Description and Operation

General description

Ignition system
In a conventional vehicle, the ignition coil produces a high voltage current which the distributor applies to each spark plug at the required time.

The Vehicle, however, uses a totally new ignition system. In this system two sensors (the camshaft position sensor and the crankshaft position sensor) indicate to the Engine Control Module (ECM) which cylinder is ready to fire. The ECM then sends an ignition signal to an electronic ignition coil. This ignition coil then produces and sends a high voltage current to the proper spark plug.

Ignition coils
The DOHC engine employs two ignition coils located directly above the No.2 and No.4 spark plugs. The coil resistances are identical for both coils. No maintenance is required. The coils should be replaced if found to be faulty.

Camshaft position (CMP) sensor
The camshaft position sensor monitors the position of the camshaft. It is mounted at the cylinder head.

Crankshaft position (CKP) sensor
It is mounted on the front of the transmission case. It senses a ring on the flywheel for crankshaft position.

High-tension leads
The high-tension leads connect the ignition coils to spark plugs.

Spark plugs
The spark plugs provide the air gap necessary to produce an arc from energy coming from the ignition coil. This arc ignites the fuel/air mixture in the engine cylinders, producing power.