| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. | 
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. | 
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. | 
Circuit  | Short to Ground  | Open/High Resistance  | Short to Voltage  | Signal Performance  | 
|---|---|---|---|---|
Calibration Mismatch  | --  | --  | --  | C0558 4B  | 
The coupling control module (CCM) receives messages from other modules over GMLAN which are needed to perform all wheel drive functions
| • | The ignition switch is in the ON position. | 
| • | Ignition voltage is greater than 9 volts. | 
The CCM receives an invalid message from ECM, EBCM, modules over GMLAN which causes the CCM to deactivate.
One or more of the following actions may occur:
| • | All Wheel Drive Off (AWD Disabled). | 
| • | Service All Wheel Drive (Service AWD). | 
| • | The condition for the DTC is no longer present. | 
| • | The DTC is not detected in 100 consecutive drive cycles. | 
| ⇒ | Diagnose any other Vehicle DTCs before attempting diagnosis of C0558. | 
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.