Circuit Description
The Auto Transfer Case (ATC) 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 Auto Transfer Case (ATC) 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 (4WD/AWD) lamp will be latched on. |
Conditions for Clearing the DTC
A history DTC will clear after a valid VIN digit is received.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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 in Electrical Diagnosis. 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 PCM EEPROM calibration Is the PCM calibration correct? | -- | Go to Step 4 | Go to Powertrain On Board Diagnostic (OBD) System Check for 4.0L, 5.3L, and 6.0L engines |
4 | Replace the transfer shift control module with the correct part number. Have all the ATC components been reconnected and properly mounted? | -- | -- |
