Logic Module

Logic module is digital computer which receives input signals from sensors, switches and components. Logic module is only unit that receives distributor pick-up signal. Logic module uses this information to calculate fuel injector pulse width (dwell period), spark advance, ignition dwell, idle speed, canister purge and EGR flow.

Logic module also monitors and tests input signals for accuracy. This monitoring is called "On Board Diagnostics". If malfunction is found in major sub-system, information is stored in module under specific fault code for later diagnosis. When fault is detected, logic module energizes power loss light on instrument panel.

When power loss light is turned on, logic module also goes into "Limp-In Mode" of operation. In this mode, logic module is substituting information from remaining sensors or switches to allow vehicle to be driven in for repairs. Significant loss of driveability usually occurs in this mode.