Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.