For 1990-2009 cars only
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
| • | 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| • | Masked ROM code has failed Checksum test indicating that masked ROM data is no longer valid.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| • | ROM code has failed Checksum test indicating that ROM data is no longer valid.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 module's relays is not able to make contact. |
Action Taken When the DTC Sets
| • | The service AWD indicator will be illuminated. |
| • | All clutch activation, slip control will be disabled. |
Conditions for Clearing the DTC
| • | Replace the transfer case shift control module. |
| • | Perform the Diagnostic System Check - Transfer Case . |
Test Description
The numbers below refer to the step numbers on the diagnostic table
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Transfer Case Control Schematics | |||
1 | Did you perform the Diagnostic System Check - Transfer Case? | Go to Step 2 | |
Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the repair? | System OK | -- | |
