Circuits Affecting Ignition Control

To properly control ignition timing, the PCM relies on the following information:
^ The engine load, manifold pressure or vacuum
^ The atmospheric, barometric, pressure
^ The engine temperature
^ The intake air temperature
^ The crankshaft position
^ The engine speed (RPM)

The Ignition Control (IC) system consists of the following components:
^ The ignition coil or modules
^ The 24X crankshaft position sensor
^ The Powertrain Control Module (PCM)
^ All connecting wires

The ignition control utilizes the following to control spark timing functions:
^ The 24X signal-The 24X crankshaft position sensor sends a signal to the PCM. The PCM uses this signal to determine crankshaft position. The PCM also utilizes this signal to trigger the fuel injectors.
^ The Ignition Control (IC) circuits-The PCM uses these circuits to trigger the ignition coil or modules. The PCM uses the crankshaft reference signal to calculate the amount of spark advance needed.