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.
Powertrain Control Module
Powertrain Control Module (PCM) is a digital computer that controls ignition system, air/fuel ratio, emission control devices, cooling fan, charging system, idle speed and cruise control system (if equipped). PCM uses input signals from various switches and sensors to control output devices in order to achieve optimum engine performance for all operating conditions. PCM contains a self-diagnostic system which stores Diagnostic Trouble Codes (DTC) if an electronic control system failure exists. DTCs may be retrieved from PCM for system diagnosis by using a scan tool. See SELF-DIAGNOSTIC SYSTEM .
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.