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 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.
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 | Did you perform the Battery Inspection/Test? | Go to Step 2 | Go to Battery Inspection/Test | ||||||||
2 | Install a scan tool. Does the scan tool power up? | Go to Step 4 | 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 Class 2 Power Mode parameter reading match the ignition switch position for all the selected positions? | Go to Step 4 | Go to Power Mode Mismatch in Body Control System | ||||||||
Does the scan tool communicate with any module on the class 2 serial data circuit? | Go to Step 5 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | |||||||||
Does the scan tool display any DTCs? | Go to Step 6 | ||||||||||
Does the scan tool display any DTC beginning with "U"? | Go to Diagnostic Trouble Code (DTC) List in Data Link Communications | Go to Step 7 | |||||||||
7 | Does the scan tool display any DTC beginning with "B"? | Go to Diagnostic Trouble Code (DTC) List in Body Control Systems |