C0550

CIRCUIT DESCRIPTION

At each power up the module runs a self test on the following:
- EEPROM Checksum
- ROM Checksum
- RAM Checksum
- RAM Malfunction
- Relay Malfunction

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- Masked ROM code has failed checksum test indicating that masked ROM data is no longer valid.
- ROM code has failed checksum test indicating that ROM data is no longer valid.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 RAM locations have failed operational test indicating that some portions of RAM are not functional.
- Motor circuit test has indicated that one of the module's relays is not able to make contact.

ACTION TAKEN WHEN THE DTC SETS

- The SERVICE indicator (AWD/4WD) 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.