Electronic Control Module: Notes

The ECM controls all functions of the closed loop system. The ECM sends an electrical signal to the vacuum control or M/C solenoid. This control signal is constantly cycling the solenoid on and off (duty cycle) as a function of the input voltages from the system sensors.

The control signal generated by the ECM is selected from 4 operational modes. These modes include: Inhibit Mode, Enrichment Mode, Open Loop Mode and Closed Loop Mode. A brief description of each mode is as follows: