Circuit Description
The transfer case shift control module uses the VIN information for calculations that are required for the different calibrations used based on axle ratio, transmission, tire size, and engine. The system does not know which calibration to use without this information.
Conditions for Setting the DTC
The transfer case shift control module does not receive a valid VIN digit for the correct application, K truck, L van or T truck within 2 seconds after power up.
Action Taken When the DTC Sets
| • | The ignition counts since last fault will be cleared. |
| • | The system will be disabled until valid VIN data is received. |
| • | The SERVICE indicator (AWD/4WD) lamp will be latched on. |
Conditions for Clearing the DTC
A history DTC will clear after a valid VIN digit is received.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
2 | Using a Scan Tool , check all the components connected to the Class 2 serial data line. Refer to Data Link Communications System Check . Is the Class 2 serial data line communicating properly? | -- | Go to Step 3 | Go to Data Link Communications System Check in Electrical Diagnosis. |
3 | Check the VCM EEPROM calibration. Is the PCM calibration correct? | -- | Go to Step 4 | Go to Powertrain On Board Diagnostic (OBD) System Check for 4.3L, Powertrain On Board Diagnostic (OBD) System Check for 5.0, 5.7L, and Powertrain On Board Diagnostic (OBD) System Check for 6.5L |
4 | Check the transfer case shift control module for the correct part number. Is the transfer case shift control module part number correct? | -- | Go to Step 5 | |
5 | Replace the transfer shift control module with the correct part number. Have all the ATC components been reconnected and properly mounted? | -- | -- |
