Ignition Coil: Description and Operation

Ignition Coil Packs:

Two separate coil packs containing a total of five independent coils are attached to a common mounting bracket. They are located above the right engine valve cover. The coil packs are not oil filled. The front coil pack contains three independent epoxy filled coils. The rear coil pack contains two independent epoxy filled coils.

When one of the 5 independent coils discharges, it fires two paired cylinders at the same time (one cylinder on compression stroke and the other cylinder on exhaust stroke).

Coil firing is paired together on cylinders:
- Number 5 and 10
- Number 9 and 8
- Number 1 and 6
- Number 7 and 4
- Number 3 and 2

The ignition system is controlled by the Powertrain Control Module (PCM) on all engines.

Battery voltage is supplied to all of the ignition coils positive terminals from the ASD relay. If the PCM does not see a signal from the crankshaft and camshaft sensors (indicating the ignition key is ON but the engine is not running), it will shut down the ASD circuit.

Base ignition timing is not adjustable on this engine. By controlling the coil ground circuit, the PCM is able to set the base timing and adjust the ignition timing advance. This is done to meet changing engine operating conditions.

The PCM adjusts ignition timing based on inputs it receives from:
- The Engine Coolant Temperature Sensor
- The Crankshaft Position Sensor (engine speed)
- The [1][2]Manifold Absolute Pressure (MAP) sensor
- The Throttle Position Sensor
- Transmission gear selection