Diagnostic Aids
By manipulating the harnesses at the various connectors it is often possible to isolate the cause of the circuit interruption. This harness can then be removed and repaired. Inspect for any damage to the harness which could cause an intermittent open circuit or backed out terminals at the instrument cluster connectors, broken connector locks, improperly formed or damaged terminals. The multimeter allows continuity of the wiring harness secondary serial data bus circuit to be checked. If the fault cannot be found in the harness, then the fault may lie in the BCM. Refer to Diagnostic Starting Point - Computer/Integrating Systems for further diagnosis.
DTC 9 - NO SERIAL DATA FROM BCM
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 |
|
Go to Step 3 | Go to Scan Tool Does Not Communicate with GMLAN Device |
| 3 |
|
Go to Step 4 | Go to Step 6 |
| 4 | Check the UART circuit between the BCM and the I/P for a short to ground. Refer to Circuit Testing
. Is a short present? |
Go to Step 7 | Go to Step 5 |
| 5 | Check the UART circuit between the BCM and the I/P for a short to voltage. Refer to Circuit Testing
. Is a short present? |
Go to Step 8 | Go to Step 9 |
| 6 | Repair the open or high resistance in the ground in the UART circuit between the electronic brake control module (EBCM) and the I/P. Refer to Wiring Repairs
. Did you complete the repair? |
Go to Step 9 | - |
| 7 | Repair the short to ground in the ground in the UART circuit between the EBCM and the I/P. Refer to Wiring Repairs
. Did you complete the repair? |
Go to Step 9 | - |
| 8 | Repair the short to voltage in the ground in the UART circuit between the EBCM and the I/P. Refer to Wiring Repairs
. Did you complete the repair? |
Go to Step 9 | - |
| 9 |
|
Go to Step 2 | System OK |