Diagnostic Instructions
| • | 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/System Description
The communication interface module (CIM) has the capability of commanding the horn, initiating door lock/unlock, or operating the exterior lamps using the serial data circuits. These functions are commanded by the OnStar® Call Center per a customer request.
Diagnostic Aids
The customer concern may have been due to a lack of cellular service in a given area. A failure in the National Cellular Network infrastructure that has since been corrected.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
OnStar Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Important:
• It is necessary to inform the OnStar® Call Center advisor that this call is for vehicle diagnostic purposes. • It is necessary to have the vehicle in an open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.
- Verify that the horn, lights, and the doors locks on the vehicle operate properly.
- Contact the OnStar® Call Center by pressing the blue OnStar® button. Verify with the OnStar® advisor that all of the remote functions (door locks, lights, or horn) work.
| ⇒ | If the applicable system does not operate properly, refer to Diagnostic System Check - Vehicle. |
| ⇒ | If unable to connect with the OnStar® call center, refer to Unable to Contact OnStar Call Center. |
| ⇒ | If the remote functions do not operate when requested, replace the CIM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for CIM replacement, setup, and programming
