NVG 233-NP1 2 Speed Automatic 4WD Transfer Case

Circuit Description
At each power up the module runs a self test on the following:
- EEPROM Checksum
- ROM Checksum
- RAM Checksum
- RAM Malfunction
- Relay Malfunction

Conditions for Setting the DTC
- Critical operational parameters stored in EEPROM have tailed 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- Masked ROM code has failed checksum test indicating that masked ROM data is no longer valid.
- ROM code has failed checksum test indicating that ROM data is no longer valid.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 AUTO/4WD lamp will be latched on and the system will be disabled.

Conditions for Clearing the MIL/DTC
- Replace the Auto transfer Case Control Module. Perform the Auto transfer Case System Check.
Testing and Inspection