Advance Control (Metro ESA & Prizm)

Ignition timing is controlled by the ECM based upon sensor input signals. ECM controls ignition timing by matching the vehicles operating conditions to preprogrammed timing advance specifications stored in ECM memory. Signals generated by the crank angle sensor are transmitted to the ECM. These signals are modified by input signals from coolant temperature sensor, MAP sensor (Prizm), throttle switch, vehicle speed sensor and monitored battery voltage.