NVG 263-NP1 (Selectable) Transfer Case

DTC C0550

Circuit Description
At each power up, the transfer case shift control module runs a self-test on the following components:
^ EEPROM Checksum
^ ROM Checksum
^ RAM Checksum
^ RAM Malfunction
^ Relay Malfunction

Conditions for Setting the DTC
^ Critical operational parameters, stored in EEPROM, have failed the Checksum test, indicating invalid data.
^ The masked ROM code has failed the Checksum test, indicating that masked the ROM data is no longer valid.
^ The ROM code has failed the Checksum test, indicating that the ROM data is no longer valid.
^ One or more ROM locations have failed the operational tests, indicating that some portions of RAM are not functional.
^ The motor circuit test has indicated that one of the modules's relays is not able to make contact.

Action Taken When the DTC Sets
The SERVICE 4WD indicator lamp will be commanded on and the system will be disabled.

Conditions for Clearing the DTC
^ Replace the transfer case shift control module.
^ Perform the Transfer Case Diagnostic System Check.





Test Description
The number below refers to the step number on the diagnostic table.
2. This step replaces the transfer case shift control module.