NVG 236-NP8 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 Checksum
^ ROM Checksum
^ RAM Checksum
^ RAM Malfunction
^ Relay Malfunction

Conditions for Running the DTC
^ The ignition is ON.
^ 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 refers to the step number on the diagnostic table
2. This step replaces the transfer case shift control module.