Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 3:
A partial malfunction in the class 2 serial data circuit uses a different procedure from a total malfunction of the class 2 serial data circuit. The following modules communicate on the class 2 serial data circuit.
- Communication interface module (OnStar®)
- Electronic brake control module (EBCM)
- Inflatable restraint sensing and diagnostic module (SDM)
- Instrument panel cluster (IPC)
- Radio
- 5: DLC terminals 2 and 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.
- 7: A poor connection at splice pack S232 will cause this condition but will not set a DTC.
- 8: An open in the class 2 serial data circuit between the DLC and splice pack S232 will prevent the scan tool from communicating with any module on the class 2 network. This condition will not set a DTC.
Scan Tool Does Not Communicate with Class 2 Device
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Link Connector (DLC) Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems |
|||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 |
|
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
| 3 | Did the scan tool communicate with any module on the class 2 serial data circuit? | Go to Step 4 | Go to Step 5 |
| 4 | Diagnose the non-communicating module by referring to the appropriate section. Did you complete the action? |
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | - |
| 5 |
|
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 6 |
| 6 | Test the DLC ground circuit at terminal 5 for an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 7 |
| 7 |
|
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 8 |
| 8 | Repair the class 2 serial data circuit between the DLC and the splice pack S232 for an open. Refer to Circuit Testing
andWiring Repairs
in Wiring Systems. Did you complete the action? |
System OK | - |