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.
System Description
The Powertrain Control Module (PCM) monitors engine operation. PCM contains a self-diagnostic system, which stores Diagnostic Trouble Codes (DTC) and compares them to On-Board Diagnostic II (OBD-II) standards.
The goal of OBD-II regulation is to provide vehicle with an on-board diagnostic system that is capable of continuously monitoring the efficiency of emission control systems, and to improve diagnosis and repair when system failures occur.
The Federal Test Procedure (FTP) sets maximum allowable emission standards. A Malfunction Indicator Light (MIL) must illuminate if a system or component either fails, or deteriorates to a point where vehicle's emissions could rise to greater than 1 1/2 times FTP standards.
DTCs may only be retrieved using an On-Board Diagnostic (OBD-II) compatible scan tool. TECH 2 scan tool is recommended by manufacturer. Other suitable aftermarket scan tools are available.
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.