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
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.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.