Test Description
The numbers below refer to the step number(s) 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 61
The numbers below refer to the step numbers on the diagnostic table.
- 2) - This step tests for proper ground on the navigation antenna.
- 3) - This step tests the condition of the navigation antenna.
Scheme 62
The number below refers to the step number on the diagnostic table.
- 2) - This step checks that the VIU is sending out the proper supply voltage.
The numbers below refer to the step numbers on the diagnostic table.
- 2) - By disconnecting the VCU you can check the three wire bus supply and carrier voltages supplied by the VIU.
- 3) - By disconnecting the VCU you can check the three wire bus supply and carrier voltages supplied by the VIU.
Scheme 63
Scheme 64
System Description
This symptom table will enable the user to verify the customer complaint and narrow it to its source. If the OnStar® system is always on, regardless of ignition state or if there is a concern with voice recognition or the remote actuated features of the OnStar® system, technicians should proceed directly to the applicable diagnostic found 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 & Operation before attempting to repair an OnStar® system.
The following number(s) refer to the step(s) on the diagnostic table.
- 3) - Determines if the OnStar® status LED has the necessary GRN LED signal circuit.
- 5) - If the GRN LED signal is shorted to voltage then the OnStar® three button assembly has been damaged. The OnStar® three button assembly has to be replaced.
Scheme 65
OnStar® Description & Operation
This vehicle will be equipped with either the 2.0 or 2.6 version of the OnStar® system. Both systems consist of a vehicle interface unit (VIU), vehicle communication unit (VCU) GPS antenna, cellular antenna, microphone and OnStar® button assembly. Both the systems interface with the vehicle audio system.
The OnStar® system version 2.0 provides the customer with impact detection, navigation instructions, emergency services, stolen vehicle tracking and recovery service, roadside assistance, door unlock, light flash and horn pulse.
The OnStar® system version 2.6 provides all the same features as version 2.0 with the addition of a hands free cellular phone. The OnStar® Personal Calling feature, if equipped, uses voice commands for dialing and programming.
Operation Of OnStar® Speech Recognition Systems
OnStar® Generation 2.6 users communicate with two 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.
