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 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.
Check for the presence of DTCs.
Check for the presence of DTCs.
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 each of the modules? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | |
Select the display DTCs function on the scan tool. 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 4 | |
Select the Powertrain Control module display DTCs function on the scan tool. Does the scan tool display any DTCs for VSS, TP Sensor or System Voltage? | Go to Diagnostic Trouble Code (DTC) List in Engine Controls -- 4.8L, 5.3L, and 6.0L or Diagnostic Trouble Code (DTC) List in Engine Controls -- 8.1L | Go to Step 5 | |
Select the ESC module display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Step 6 | ||
6 |
Important: Do not turn the ignition OFF after clearing the DTCs. Does the scan tool display any DTCs? | Go to Step 7 | System OK |
7 | Does the scan tool display DTC C0550 or C0551? | Go to Step 8 | |
8 | Does the scan tool display DTC C0870? | Go to DTC C0870 | Go to Step 9 |
9 | Does the scan tool display all of the following DTCs C0575, C0580, C0585 and C0590? | Go to DTC C0690 | Go to Step 10 |
10 | Does the scan tool display any of the following DTCs C0575, C0580, C0585 or C0590? | Go to Step 11 | |
11 |
Important: Do not turn the ignition OFF after clearing the DTCs. Does the DTC reset? |