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.
Data Link References
This table identifies which serial data link that a particular module uses for in-vehicle data transmission and communication with the scan tool. Some modules may use more than one data link to communicate. Some modules may use different circuits for functional and diagnostic communication. Use the schematic reference link in the table for additional information. This table is used to assist in correcting a communication malfunction. For the description and operation of these serial data communication circuits refer to Data Link Communications Description and Operation .
| Control Module | Data Link Type | Diagnostic Procedure |
|---|---|---|
| Schematic Reference: Data Link Communications Description and Operation | ||
| Body Control Module (BCM) |
|
Scan Tool Does Not Communicate with Class 2 Device |
| Communication Interface Module (OnStar) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device |
| Digital Radio Receiver | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Electronic Brake Control Module (EBCM) |
|
Scan Tool Does Not Communicate with Keyword Data Line |
| Engine Control Module (ECM), with L61 |
|
Scan Tool Does Not Communicate with Keyword Data Line |
| Inflatable Restraint Sensing and Diagnostic Module (SDM) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device |
| Instrument Panel Cluster (IPC) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device |
| Power Steering Control Module (PSCM) | Class 2 | Scan Tool Does Not Communicate with Class 2 Device |
| Powertrain Control Module (PCM), with L66 |
|
Scan Tool Does Not Communicate with Keyword Data Line |
| Radio | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Transmission Control Module (TCM), with L61 |
|
Scan Tool Does Not Communicate with Keyword Data Line |
NO RELATED
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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.