Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS .
OnStar® Steering Wheel Control Functions Inoperative
Some vehicles equipped with the OnStar® system have the capability of accessing voice mailboxes and other automated phone systems by means of the steering wheel controls, while the OnStar® Personal Calling (OPC) feature is in use, If the "Talk" or "Mute" button (depending upon the vehicle) on the steering wheel controls are depressed during an OPC call, the Vehicle Communication Interface Module receives the message on the Class 2 serial data bus from either the radio, driver information module, or body control module. This message is interpreted as a request to turn any spoken numbers into Dual Tone Multi-Frequency (DTMF) tones to be delivered over the airwaves to the phone system the user is communicating with. Complete instructions for operation of these features can be found in the information provided to the customer with the OnStar® system.
The steering wheel controls are a resistor network that consist of multiple momentary contact switches and a series of resistors. The switches and resistor network are arranged so that each switch has a different resistance value. When a switch is pressed, a voltage drop occurs in the resistor network, which produces a specific voltage value unique to the switch selected, to be interpreted by either the radio, dash integration module, or body control module. In the event the OnStar® steering wheel control functions are inoperative, technicians should refer to DIAGNOSTIC SYSTEM CHECK -- ENTERTAINMENT SYSTEM to begin diagnosis of the steering wheel control concern.
Vehicle Communication Interface Module (VCIM)
The VCIM is a 3-watt cellular device that allows the user to communicate data and voice signals over the national cellular network. It is powered by a fused, battery positive voltage circuit, connected through vehicle wiring to the 3-button assembly and the radio, and attached by means of coax cables to the cellular and navigation antennas. Ground for the module is accomplished by means of dedicated circuits that are routed with body wiring systems to chassis ground points. The module houses two modems, one to process global positioning system (GPS) data, and the other for cellular information. Satellites orbiting earth are constantly transmitting signals of their current location, from which the OnStar® system is able to pinpoint its own location. The navigation antenna receives these GPS signals and provides the data to the VCIM to be processed. The VCIM communicates with the rest of the vehicle over the class 2 serial data bus. Ignition state is determined by the VCIM through class 2 messaging. The module also has the capability of commanding the horn, door lock/unlock and operating the exterior lamps using the class 2 serial data circuit. When an OnStar® key press is made, a class 2 message is sent to the audio system to mute all radio functions and transmit OnStar® originated audio. After the audio system is muted, the OnStar® signals are transmitted to the audio system on the cellular telephone voice signal circuit, and returned to the module on the cellular telephone voice low reference circuit. The cellular modem connects the OnStar® system to the cellular carrier's communication system by interacting with the national cellular infrastructure. The module sends and receives all cellular communications over the cellular antenna and cellular antenna coax.
OnStar® Microphone
The OnStar®, or cellular, microphone can be part of the rearview mirror assembly, or on some vehicle lines, can be a separate, stand alone unit. In either case, the microphone is supplied voltage on the cellular microphone signal circuit, while voice data from the user is sent back to the VCIM by means of either a cellular microphone low reference circuit or a drain wire.
This vehicle will be equipped with either separate cellular and navigation antennas, or a combination cellular and navigation antenna, which brings the functions of both into a single part.
The cellular antenna is the component that allows the OnStar® system to send and receive data over airwaves by means of cellular technology. This antenna is connected at the base to a coax cable that plugs directly into the VCIM. The navigation antenna is used to collect the constant signals of the orbiting satellites. Within the antenna, is housed a low noise amplifier that allows for a more broad and precise reception of this data. Current GPS location is collected by the module every time a key press is made. The OnStar® Call Center also has the capability of pinging the vehicle during an OnStar® call, which commands the module to retrieve the latest GPS location and transmit it to the OnStar® Call Center.
A history location of the last recorded position of the vehicle is stored in the module and marked as aged. In the event the VCP loses or is removed from power, this history location is used by the OnStar® Call Center as a default. Actual GPS location may take up to 10 minutes to register in the event of a loss of power. This antenna requires a clear and unobstructed path to the satellites in the sky. Window tinting on vehicles may interfere with the GPS sensor functions, depending upon the amount of darkening and/or metallic particles that are embedded in the film of the tinting material.
Deactivated OnStar® Accounts
In the event a customer has not renewed their OnStar® account after expiration or the account was never activated, OnStar® will make a discrete cellular call to the vehicle to deactivate the OnStar® system. Before taking this action, customers are notified that the OnStar® system in their vehicle will be deactivated unless they elect to renew the account. After the vehicle has been successfully deactivated, customers will experience the following when attempting to contact OnStar from their vehicle
- During an OnStar® Call Center button press, the customer will be connected to a dedicated sales team who can sell an OnStar® subscription and reactivate the vehicle. Depending on the type of OnStar® hardware in the vehicle, the customer may first hear a demonstration message stating there is no current OnStar® subscription for the vehicle, and directing the customer what to do to activate services.
- During an Emergency button press, a demo message will be played indicating the service has been deactivated.
- OnStar® Personal Calling (OPC) will not be available, as this feature requires the customer to have a current OnStar® account, Attempts to use this feature may result in cellular connection failure messages and the inability to connect to the number dialed.
It is of particular note, that when an OnStar® system is successfully deactivated, it will NOT attempt to connect to the OnStar® Call Center in the event of a collision or if the vehicle's front airbags deploy for any other reason.
Certain vehicles that have never had an active OnStar® account, that have been deactivated, may be unable to establish a connection with the OnStar® Call Center. When normal published diagnostic procedures do not indicate a possible cause for the no connect concern, the vehicle may have been deactivated. For deactivated vehicles, a no connect response should be considered normal operation. Further diagnosis and subsequent repair is only necessary should the customer elect to become an active OnStar® subscriber.
OnStar® Reconfiguration Procedure
Within the VCIM are a set of unique numbers that identify the OnStar® customer and the specific vehicle the module resides in. These numbers, the station identification number (STID) and the electronic serial number (ESN) are transmitted over the cellular network when an OnStar® key press is made and are essential for proper identification and connection to the OnStar® Call Center. In the event the VCIM requires replacement, the OnStar® reconfiguration procedure must be performed. This procedure allows for the new STID and ESN within the replacement module to overwrite the old numbers and update customer and vehicle information at the OnStar® Call Center. The Reconfiguration process is explained within the Vehicle Communication Interface Module replacement procedure, or the OnStar® Reconfiguration Procedure found in the Cellular Communication diagnostic information and procedures section.
OnStar® Personal Calling
The hand free, OnStar® Personal Calling (OPC) cellular phone feature is an additional option to the OnStar® system. This feature is already embedded within the VCIM, however, it must be activated by an OnStar® advisor. This is done most often during the initial OnStar® configuration, if the home location of the vehicle is in a geographic area where OnStar® Personal Calling is available. In the event this feature is not enabled, customers may connect to the OnStar® Call Center by pressing the blue OnStar® button, and asking an advisor if OPC is available in their area. Users of the Generation 5 OnStar® system can verify the system has been configured for OnStar® Personal Calling by pressing the answer/end call button, waiting for the system to respond "OnStar Ready" then speaking "dial". If the system responds "phone unavailable" the system has not been configured for OPC. All other responses confirm that OPC has been enabled.
OnStar® Steering Wheel Controls
Some vehicles equipped with the OnStar® system have the capability of accessing voice mailboxes and other automated phone systems by means of the steering wheel controls, while the OnStar Personal Calling (OPC) feature is in use. If the "Talk" or "Mute" button (depending upon the vehicle) on the steering wheel controls are depressed during an OPC call, the Vehicle Communication Interface Module receives the message on the Class 2 serial data bus from either the radio, driver information module, or body control module. This message is interpreted as a request to turn any spoken numbers into Dual Tone Multi-Frequency (DTMF) tones to be delivered over the airwaves to the phone system the user is communicating with. Complete instructions for operation of these features can be found in the information provided to the customer with the OnStar® system.
The steering wheel controls are a resistor network that consist of multiple momentary contact switches and a series of resistors. The switches and resistor network are arranged so that each switch has a different resistance value. When a switch is pressed, a voltage drop occurs in the resistor network, which produces a specific voltage value unique to the switch selected, to be interpreted by either the radio, driver information module, or body control module.
OPC Features
The following is an abbreviated list of features that may have an impact for the technician when servicing or diagnosing an OnStar® system. For a full list of OnStar® Personal Calling features, consult the owners guide provided to the customer with the OnStar® system.
Voice Feedback
The OPC system has the capability of responding to the user with either an automated voice response or with a tone or "beep". These two types of responses can be switched back and forth by pressing the answer/end call button, waiting for the system to respond "OnStar Ready" and speaking the phrase "voice feedback". The system will then respond, "voice feedback is now on/off".
OPC Security/System Lock
Customers have the capability to lock their OPC system by pressing the answer/end call button, speaking "security" and entering a four-digit code. Once this process is complete, the user must enter the code before OnStar® Personal Calling is available. In the event the customer cannot remember their code and is unable to use their system, they can press the blue OnStar button and speak to an advisor to unlock the system by means of a discrete cellular call to the vehicle.
Customers have the ability to store telephone numbers within the module, referenced by a "nametag" for the convenience of frequently dialed numbers, This process is initiated by pressing the answer/end call button, waiting for the system response, then speaking the response "store". The system will respond with "number please" at which time the user should enter the number desired to be stored. Once complete, saying the word "store" again lets the system know you are finished entering the number. At this time, the system will elicit the user to assign a "nametag" to that number. From this point forward, the user can dial this number by initiating the OPC feature, speaking the word "call", and repeating the nametag assigned. To delete a nametag, the user should initiate OPC, say "delete" then speak the nametag to be removed. In the event a nametag cannot be deleted in spite of repeated attempts from several speakers, the OnStar® module will require replacement.