Unable to Contact OnStar Call Center

Unable to Contact OnStar Call Center

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Circuit/System Description

The telematics communication interface control module is a cellular device that allows the user to communicate data and voice signals over the national cellular network. When an OnStar keypress is made, the telematics communication interface control module activates and connects the system to the cellular carriers communication system by interacting with the national cellular infrastructure. The module sends and receives all cellular communications over the cellular phone and navigation antenna and cellular antenna coax.

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 at the time of the customers failed connection that has since been repaired may also have been the cause.
* If an OnStar(R) emergency call is able to successfully connect the vehicle to the OnStar(R) Call Center when an OnStar(R) Call Center button press is not, there may be a failure in the ability of the OnStar(R) system in the vehicle to be recognized by the local cellular carrier.
* If the prompt "OnStar(R) request ended" is heard, without pressing the white dot button at the end of the OnStar(R) keypress, the OnStar(R) system at one time has made a successful cellular connection, but was unable to complete the call.
* 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.

Reference Information
Schematic Reference

* OnStar Schematics (OnStar Schematics)
* Antenna Coaxial/Connector Cable Identification Table (Application and ID)

Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

OnStar Description and Operation (OnStar)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

EL-49903 GM OnStar Antenna Diagnostic Tool Kit

Circuit/System Verification

Note: The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning key on for the GPS satellites to acquire vehicle signal.

Ignition ON, wait 5 minutes, then contact the OnStar call center consultant by pressing the blue OnStar button. A call center consultant should answer the call, verifying the vehicle OnStar system is functioning and the consultant can locate the vehicle.

If the unit does not connect to the OnStar Call Center, verify the vehicles OnStar subscription is valid, has not expired and is in good standing.

Circuit/System Testing

1. Ignition OFF, disconnect both the GPS and cell coax cable connectors at the K73 telematics communication interface control module.
2. Connect the EL-49903 to the K73 telematics communication interface control module, place the test antenna on the roof of the vehicle.
3. Ignition ON, wait 5 minutes, and then contact the OnStar call center consultant by pressing the blue OnStar button. A call center consultant should answer the call.

• If the unit does not connect to the OnStar Call Center and the subscription is valid, use a scan tool to obtain and record the following information: Electronic Serial Number (ESN), Station Identifier (STID), GM 8-digit part number, Mobile Identification Number (MIN), Mobile Dialed Number (MDN), Transceiver ID (Trans ID) and call GM TAC.

4. Request the consultant to verify the vehicle location to confirm the GPS system is functioning.

• If the OnStar GPS does not function, replace the K73 telematics communication interface module.

5. Ignition OFF, perform the coax cable test on the coax cable, refer to Component Testing. The coax cable should pass the test.

• If the coax cable does not pass the test, replace the coax cable.

6. If all circuits test normal, replace the T4 cellular phone and navigation antenna.

Component Testing

Caution: Refer to Test Probe Caution (Test Probe Caution).

Note: Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.

To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test
1. Ignition OFF, disconnect the GPS and cellular phone coax cable at both components.
2. Test both for less than 5 ohm between both ends of the coax cables center terminals.

• If greater than the specified range, replace the failed coax cable.

3. Test for greater than 10k ohm between the coax cable center wire and the outer coax shield.

• If less than the specified range, replace the coax cable.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Mobile Telephone and Vehicle Location Antenna Base Replacement (Mobile Telephone and Vehicle Location Antenna Base Replacement)
* Control Module References (Programming and Relearning) for telematic communication interface control module replacement, setup, and programming