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.
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 | Perform the Battery Inspection/Test. Does the battery pass the 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 | |
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 positions for OFF, RUN and CRANK 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 | ||
Does the scan tool display any DTCs? | Go to Step 6 | ||
Does the scan tool display any DTC beginning with "U"? | Go to Step 7 | ||
7 | Does the scan tool display any DTC beginning with "P"? | Go to Diagnostic Trouble Code (DTC) List 4.3 L, Diagnostic Trouble Code (DTC) List 4.8 L,5.3 L,6.0 L, Diagnostic Trouble Code (DTC) List 6.6 L or Diagnostic Trouble Code (DTC) List 8.1 L in Engine Controls | Go to Step 8 |
8 | Does the scan tool display any DTC beginning with "B"? |