DTC 004

DTC 004

Circuit Description
At each power up the transfer case shift control module (TCCM) runs a self test on:
^ Electronically erasable programmable read-only memory (EEPROM) Checksum
^ Read-only memory (ROM) Checksum
^ Random access memory (RAM) Checksum
^ RAM Malfunction

DTC Descriptor
This diagnostic procedure supports this DTC:
DTC 004 ECU Malfunction

Conditions for Running 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.

Conditions for Clearing the DTC
The condition for setting the DTC is not present and a momentary loss of battery power at the battery positive voltage circuit.

Test Description

Steps 1-3:

This number corresponds to the step number on the diagnostic table.
2. This step replaces the TCCM.