Test Description
The numbers below Refer to the step numbers on the diagnostic table.
- 2. Lack of communication may be due to a partial malfunction or a total malfunction of the class 2 serial data circuit. The specified procedure will determine the condition.
- 5. The presence of DTCs which begin with "U" indicate some other system control module is not communicating.
Scheme 65
Scheme 66
The number below refers to the step number on the diagnostic table.
- 2. This step checks that the Vehicle Communication Interface Module is sending out the proper supply voltage.
Scheme 67
The number(s) below Refer to > the step number(s) on the diagnostic table.
- 2. This step tests the condition of the Cellular Antenna.
- 3. This step tests the condition of the cellular antenna coax and for proper ground of the cellular antenna.
Scheme 68
The number below refers to the step number on the diagnostic table.
- 2. This step checks that the Vehicle Communication Interface Module is sending out the proper supply voltage.
Scheme 69
The number below refers to the step number on the diagnostic table.
- 2. This step tests the at rest state of the Keypad Signal circuit.
Scheme 70
System Description
This symptom table will enable the user to verify the customer complaint and narrow it to its source. If there is a concern with voice recognition or OnStar® steering wheel control function, technicians should proceed directly to the applicable diagnostic in Symptoms - Cellular Communication .
Important: To successfully diagnose and repair the OnStar® system it is necessary to comprehend its operation. Technicians should read and understand the OnStar Description and Operation before attempting to repair an OnStar® system.
The numbers below Refer to the step numbers on the diagnostic table.
- 3. Determines if the OnStar® status LED has the necessary Green LED signal circuit voltage.
- 5. If the green LED signal is shorted to voltage then the OnStar® three button assembly has been damaged and the OnStar® three button assembly must be replaced.
Scheme 71
The number below refers to the step number on the diagnostic table.
- 7. If the Cellular Telephone Voice Low Reference circuit is shorted to voltage the Vehicle Communication Interface Module has been damaged and requires replacement.
Scheme 72
OnStar Description and Operation
This vehicle uses the Generation 5 version of the OnStar® system. This system consists of the following components
- Vehicle communication interface module (VCIM)
- OnStar® button assembly
- Microphone
- Cellular antenna
- Navigation antenna
This system also interfaces with the factory installed vehicle audio system.
Operation of the Hands Free Cellular Phone
OPC operates similar to most hand held cellular phones in that the availability for its usage is based on minutes or "units". The customer must have a current OnStar® subscription, as this feature cannot be utilized without it. To use OnStar® Personal Calling, the customer must also purchase units as outlined in the owners guide provided with the OnStar® system. When the customer purchases minutes, an OnStar® advisor "loads" these minutes into the VCIM over the airwaves at the time of the request, or through a discrete cellular call to the vehicle at a later time.
Once loaded into the module, the units may be used for non-international, outbound cellular phone calls and connection with the OnStar® Virtual Advisor. Units begin to deplete (one unit is equal to one minute) as the customer makes outbound phone calls, answers inbound phone calls, or while connected to the OnStar® Virtual Advisor. In addition, units also have an expiration date, depending upon the type of units purchased. This date is established when the download is performed and any remaining units expire when the date within the VCIM (which is based on current date and time transmitted by GPS satellites) has passed. At any time, the user can press the answer/end call button, say "Units" and verify the number of units remaining.
During a hands free call, the microphone and audio system operate the same way as a standard OnStar® call. When the answer/end call button is pressed, the audio system will mute; the OnStar® system will then return the prompt "OnStar Ready". At this point there are specific commands set to initiate a cellular call. If the vehicle receives a call when the radio is on, the audio system will mute and an audible ring will be heard though the speakers. The call will be answered when the answer/end call button is pressed.
The Vehicle Communication Interface Module interprets all of the voice-activated commands. A complete list of these commands is supplied in the information provided to the customer. If the information is not available to reference, at any command prompt the caller can say "HELP" and the VCIM will return an audible list of available commands. If the customer concern is not being understood or not being heard by the OnStar® system, the user should place a call to the OnStar call center to verify proper operation of the microphone. Following this description is an example of the commands and the OnStar system responses. A complete list of commands is supplied in the information provided to the customer with the OnStar® system.
Mobile Identification Number and Mobile Directory Number
The Generation 5 VC1M utilizes two numbers for cellular device identification, call routing and connection, a MIN (Mobile Identification Number) and a MDN (Mobile Directory Number). The MIN represents the number used by the cellular carrier for call routing purposes while the MDN represents the number dialed to reach the cellular devise. Although technicians have the capability to change these numbers by means of the scan tool, this should ONLY be done at the direction of and with explicit instruction from the General Motors Technical Assistance Center (GM TAC).
Scheme 73
Operation of the OnStar® Speech Recognition Systems
OnStar® Generation 5 users communicate with 2 speech recognition systems. Speech recognition allows the user to speak to one computer in the vehicle, and one reached over a phone line. The computer tries to understand the user's command, and responds by speaking back, or by taking the appropriate action, e.g. dialing the phone.
- Personal Calling uses a speech recognition system that resides in the vehicle. When the user presses the dot button, the system states, Ready, and listens for the user's command. The user can speak commands to control the hands-free phone.
- Virtual Advisor is a remote speech recognition system that the caller access by making a phone call. The user connects to Virtual Advisor by requesting it during personal calling use. The user is then transferred to the Virtual Advisor server and talks to it via a cellular connection.
The OnStar® speech recognition systems use speech technology that is designed to understand a wide range of American English speakers. Although there is no one right way to speak English, the system will work best when users try to modify their pronunciation should they encounter difficulty. Users who do not obtain good results are advised to try the tips and workarounds found in this section.
