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 Serial Data Link
The class 2 serial data communications circuit is provided at Pin 2 of the DLC.
The class 2 serial data link allows the following modules to communicate and share data with each other:
- Powertrain control module (PCM)
- Inflatable restraint sensing and diagnostic module (SDM)
- Theft deterrent control module
- Vehicle interface unit (VIU)
The class 2 serial data link allows a scan tool to communicate with the above modules for diagnostic and testing purposes.
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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.