Ignition Control (IC) System (1.6L)

Ignition timing is calculated by PCM based on current engine status. PCM controls ignition timing to a precise point by matching vehicle operating conditions to preprogrammed timing advance specifications stored in PCM memory. PCM receives signals indicating vehicle speed, manifold vacuum, throttle position and engine coolant temperature. PCM uses reference pulses from camshaft position sensor to determine engine speed. PCM cannot operate ignition system without engine speed signal from camshaft position sensor. PCM controls ignition timing by controlling ignition coils.

Ignition timing is controlled by PCM and is not adjustable. See IGNITION TIMING in appropriate ON-VEHICLE ADJUSTMENTS article.