Circuit Description
At each power up the module runs a self test on the following:
Conditions for Setting the DTC
|     •  | Critical operational parameters stored in EEPROM have failed checksum
test indicating invalid data. | 
 
|     •  | Masked ROM code has failed checksum test indicating that masked
ROM data is no longer valid. | 
 
|     •  | ROM code has failed checksum test indicating that ROM data is
no longer valid. | 
 
|     •  | One or more RAM locations have failed operational test indicating
that some portions of RAM are not functional. | 
 
|     •  | Motor circuit test has indicated that one of the module's relays
is not able to make contact. | 
 
Action Taken When the DTC Sets
The SERVICE indicator (AWD/4WD) lamp will be latched on and the system
will be disabled.
Conditions for Clearing the DTC
|     •  | Replace the transfer case shift control module. | 
 
|     •  | Perform the transfer case shift control module. |