Ignition Control Module: Description and Operation
PURPOSEThe igniter temporarily interrupts the primary current with the ignition signal (IGT signal) from the Engine Control Module (ECM) and generates sparks at the Spark Plug. Also, as a fail-safe measure, when ignition occurs an ignition confirmation signal (IGF signal) is sent to the ECM.
OPERATION
Computers generally produce low amperage signals as outputs, the Igniter is essentially an electronic relay. It receives a "trigger" from the ECM and responds by turning a higher amperage current to the Ignition Coil on and off.
CONSTRUCTION
The Igniter consists of a power transistor and circuitry to provide a tachometer output.