Logic Module

The logic module is a digital microprocessor computer. The module receives input signals from various sensors, switches and components. This information is used by the computer to calculate fuel injector pulse width ("ON" time), spark advance, ignition dwell, idle speed, canister purge and EGR flow.

The module also monitors and tests input signals for accuracy. This monitoring is called "On Board Diagnostics". If a malfunction is found in a major sub-system, the information is stored in the module under a specific fault code for later diagnosis. When a fault is detected, the module energizes the Power Loss Lamp on the instrument panel.

When this lamp is lit on instrument panel, logic module goes into "Limp-In Mode" of operation. In this mode, the logic module is substituting information to allow the vehicle to be driven in for repairs. A significant loss of driveability usually occurs in this mode.