Circuit Description
At each power-up, the transfer case shift control module runs
a self-test on the following:
Conditions for Running the DTC
| • | System voltage is 9-16 volts. |
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 not valid. |
| • | ROM code has failed Checksum test indicating that ROM data is
not valid. |
| • | One or more ROM locations have failed operational test indicating
that some portions of RAM are not functional. |
| • | Motor circuit test has indicated that one of the modules relays
is not able to make contact. |
Action Taken When the DTC Sets
| • | The SERVICE 4WD indicator remains illuminated and the system is
disabled. |
| • | No further mode changes for the current ignition cycle. |
Conditions for Clearing the DTC
| • | Replace the transfer case shift control module. |
| • | Perform the Diagnostic System Check - Transfer Case. |
Test Description
The number below refers to the step number on the diagnostic table
-
This step replaces the transfer case shift
control module.
