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 symptom list in Symptoms will determine the correct diagnostic procedure to use.
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 Powertrain Control Module?  | Go to Step 3  | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications  | |
Select the PCM display DTC function on the scan tool. Does the scan tool display any cruise control DTCs?  |