Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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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.
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Perform diagnostics for powertrain DTC's first before addressing other DTC's. They can be responsible for setting other DTC's.
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The presence of DTC's indicates that the transfer case shift control module has detected a fault. Go to symptoms for other concerns.
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 powertrain control module display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.3L | Go to Step 4 | |
Check the transfer case shift control module for DTC's. The transfer case shift conrtol module is not a class 2 device. DTC's are displayed on the transfer case shift control switch. Refer to Diagnostic Trouble Code (DTC) Displaying Are any DTC's present? | Go to Symptoms - Transfer Case |
