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.
Class 2 Circuit Description
The data link connector (DLC) allows a scan tool to communicate with the class 2 serial data circuit. Class 2 serial data is transmitted on a single wire at an average of 10.4 Kbps. The bus is active at 7 volts nominal and inactive at ground potential. When the ignition switch is in RUN, and a scan tool is connected to the DLC, the powertrain control module (PCM) will start communicating diagnostic information over the class 2 serial data circuit.
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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.