BW 4493/4494 - Transfer Case

DTC C0550

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

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0550 ECU Malfunction

Conditions for Running the DTC
^ The ignition is ON.
^ The system voltage is 9 - 18 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 currently valid.
^ ROM code has failed Checksum test indicating that ROM data is not currently valid.
^ One or more ROM locations have failed operational test indicating that some portions of RAM are not functional.

Action Taken When the DTC Sets
^ The SERVICE 4WD indicator will be latched on and the system will be disabled.
^ The transfer case control switch will display the current position LED while DTC C0550 is current, but further shifting will be disabled.

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

Test Description

Step 1 - Step 2:

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