The numbers below refer to the step numbers on the diagnostic table.
Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or GMLAN circuit or due to a total malfunction of the class 2 serial data circuit or GMLAN circuit. The specified procedure will determine the particular condition.
The symptom list in Symptoms will determine the correct diagnostic procedure to use.
The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before you perform tests.
Step | Action | Yes | No | ||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Perform the Battery Inspection/Test. Refer to Battery Inspection/Test . Does the battery pass the test? | Go to Step 2 | -- | ||||||||||||||||||||||||||||||||||||||||
2 |
Does the scan tool power up? | Go to Step 3 | Go to Scan Tool Does Not Power Up in Data Link Communications | ||||||||||||||||||||||||||||||||||||||||
3 |
Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
Does the ignition switch parameter reading match the ignition switch position for all switch positions? | Go to Step 4 | Go to Power Mode Mismatch in Body Control System | ||||||||||||||||||||||||||||||||||||||||
Does the scan tool communicate with all modules on the class 2 serial data circuit? | Go to Step 5 | Go to Data Link References in Data Link Communications | |||||||||||||||||||||||||||||||||||||||||
Does the scan tool display any DTCs? | Go to Step 6 | ||||||||||||||||||||||||||||||||||||||||||
Does the scan tool display any DTCs which begin with a "U"? | Go to Data Link References in Data Link Communications | Go to Step 7 | |||||||||||||||||||||||||||||||||||||||||
7 | Does the scan tool display DTC B1000, B1004, B1007 or B1009? | Go to Diagnostic Trouble Code (DTC) List in Body Control System |