The number(s) below refer to the step number(s) on the diagnostic table.
Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
The presence of DTCs which begin with U indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Step  | Action  | Yes  | No  | 
|---|---|---|---|
1  | Install a scan tool. Does the scan tool power up?  | Go to Step 2  | Go to Scan Tool Does Not Power Up in Data Link Communications  | 
 Does the scan tool communicate with the body control module?  | Go to Step 3  | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications  | |
3  | Select the body control module display DTCs function on the scan tool. Does the scan tool display any DTCs?  | Go to Step 4  | Go to Symptoms  | 
Does the scan tool display any DTCs which begin with a U?  | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications  | Go to Step 5  | |
5  | Does the scan tool display DTC B1397, B1398, or B1480?  | Go to Diagnostic Trouble Code (DTC) List/Type in Body Control System  |