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.
Circuit Description
The serial data communication among the control modules is performed through multiple serial data communication links. The class 2 serial data line is always present. The high speed GMLAN or controller area network (CAN) may be present for different vehicle options. The data link connector (DLC) allows a scan tool to communicate with the modules on class 2 or high speed GMLAN serial data lines. In order for the scan tool to communicate with the modules on high speed GMLAN link, a CANdi module is needed. The CANdi module behaves as an interface between the scan tool and the high speed GMLAN data link. The CAN is used for functional communication only, among the modules connected to it.
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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.