C0550

DTC C0550

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

DTC Descriptor
This diagnostic procedure supports this DTC:
DTC C0550 ECU Malfunction

Conditions for Running the DTC
^ The ignition is ON.
^ The 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^ Masked ROM code has failed Checksum test indicating that masked ROM data is no longer valid.
^ ROM code has failed Checksum test indicating that ROM data is no longer valid.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 relays is not able to make contact.

Action Taken When the DTC Sets
^ The SERVICE AWD indicator is illuminated for the remainder of the current ignition cycle.
^ All clutch activation, slip control is disabled.

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

Test Description





These numbers correspond to the step numbers on the diagnostic table.
2. This step replaces the transfer case shift control module.