At each power up, the transfer case shift control module runs a self-test on the following components:
• | EEPROM Checksum |
• | ROM Checksum |
• | RAM Checksum |
• | RAM Malfunction |
• | Relay Malfunction |
• | Critical operational parameters, stored in EEPROM, have failed the Checksum test, indicating invalid data. |
• | The masked ROM code has failed the Checksum test, indicating that masked the ROM data is no longer valid. |
• | The ROM code has failed the Checksum test, indicating that the ROM data is no longer valid. |
• | One or more ROM locations have failed the operational tests, indicating that some portions of RAM are not functional. |
• | The motor circuit test has indicated that one of the modules's relays is not able to make contact. |
The SERVICE 4WD indicator lamp will be commanded on and the system will be disabled.
• | Replace the transfer case shift control module. |
• | Perform the Transfer Case Diagnostic System Check. |
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | Go to Step 2 | |
Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the repair complete? | Go to Step 3 | -- | |
3 |
Does the DTC reset? | -- | System OK |