Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Cadillac Escalade EXT. However, it is still accessible from the selected car via links, so may be relevant.
- 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 at the time of the customer's failed connection that has since been repaired may also have been the cause.
- If an OnStar Emergency call is able to successfully connect the vehicle to the OnStar Call Center when an OnStar Call Center button press is not, there may be a failure in the ability of the OnStar system in the vehicle to be recognized by the local cellular carrier.
- If the prompt "OnStar request ended" is heard without depressing the white "Dot" button at the end of the an OnStar keypress, the OnStar system at one time has made a successful cellular connection but was unable to complete the call. If repeated calls are placed with this result, contact the General Motors Technical Assistance Center.
Unable to Contact OnStar Call Center
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: OnStar Schematics DEFINITION: When the OnStar® Call Center button is pressed, no connection is made to the OnStar® Call Center. |
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| 1 | Did you perform the Cellular Communication Diagnostic System Check? | - | Go to Step 2 | Go to Diagnostic System Check - Cellular Communication |
| 2 |
IMPORTANT:
It is important 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.
|
- | Go to Diagnostic Aids | Go to Step 3 |
| 3 | Other than the prompt "Unable to Contact OnStar", were any other tones or messages heard? | - | Go to Step 4 | Go to Step 6 |
| 4 | Was a fast, busy beep heard? | - | Go to Step 7 | Go to Step 5 |
| 5 | Were any cellular messages heard? | - | Record all cellular messages, use the scan tool to access the STID, ESN, and Transceiver I.D. and contact the General Motors Technical Assistance Center | Go to Step 8 |
| 6 | Was the prompt "OnStar Request Ended" heard? | - | Go to Diagnostic Aids | - |
| 7 |
IMPORTANT:
Placing an emergency call to the OnStar Call Center should only be made if the diagnosis of the system leads to this step. Immediately after an OnStar advisor picks up the call, they should be told that this call is for diagnostic purposes only and there is no emergency. Press the OnStar® Emergency button.Does the emergency keypress call make a connection to the OnStar® Call Center within 10 minutes? |
- | Go to Diagnostic Aids | Go to Step 8 |
| 8 | Inspect the Cellular antenna for exterior damage. Is the antenna assembly damaged? |
- | Go to Step 12 | Go to Step 9 |
| 9 |
|
- | Go to Step 10 | Go to Step 11 |
| 10 | Measure the resistance of the cellular antenna coax center conductor from end to end. Does the resistance measure greater than the specified value? |
1Ω | Go to Step 11 | Go to Step 13 |
| 11 | Replace the Cellular antenna coax. Did you complete the replacement? |
- | Go to Step 14 | - |
| 12 | Replace the Cellular antenna assembly. Did you complete the replacement? |
- | Go to Step 14 | - |
| 13 | Test the following circuits for an open:
Refer to CIRCUIT TESTING in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Contact the General Motors Technical Assistance Center |
| 14 | Operate the system in order to verify the repair. Did you correct the condition? |
- | System OK | Go to Step 2 |