NVG 263-NP1 (Selectable) Transfer Case

DTC C0550





Test 1-2

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

Conditions for Setting the DTC
^ Critical operational parameters stored in EEPROM have failed Check sum test indicating invalid data.
^ Masked ROM code has failed Check sum test indicating that masked ROM data is no longer valid.
^ ROM code has failed Check sum test indicating that ROM data is no longer valid.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's relays is not able to make contact.

Action Taken When the DTC Sets
The SERVICE 4WD indicator 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 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.