# : Servicing Vehicles Upgraded to OnStar Generation 6 Digital-Capable System - Follow Information Below - (Apr 9, 2009)

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1 # : Servicing Vehicles Upgraded to OnStar Generation 6 Digital-Capable System - Follow Information Below - (Apr 9, 2009) Subject: Servicing Vehicles Upgraded to OnStar Generation 6 Digital-Capable System (Follow Information Below) Models: Buick LeSabre Buick Rendezvous 2004 Buick Rainier, Regal Buick Century Cadillac DeVille, Seville Cadillac CTS Cadillac Escalade Models Cadillac SRX, XLR 2005 Cadillac CTS, STS Chevrolet Impala, Monte Carlo Chevrolet TrailBlazer Models Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe Chevrolet Cavalier, Venture 2004 Chevrolet Colorado Chevrolet Malibu, Malibu Maxx 2005 Chevrolet Cobalt, Corvette, Equinox GMC Envoy Models GMC Savana, Sierra, Yukon Models 2004 GMC Canyon Oldsmobile Aurora Oldsmobile Bravada Oldsmobile Silhouette Pontiac Aztek Pontiac Bonneville Pontiac Montana, Sunfire 2004 Pontiac Grand Prix 2005 Pontiac G6, Pursuit (Canada) HUMMER H Saturn VUE Saturn ION Saturn L-Series Equipped with OnStar (RPO UE1) Please Refer to GMVIS Attention: This bulletin is being issued to provide dealer personnel with information and the procedures to diagnose an upgraded OnStar Generation 6 Digital-Capable system.

2 Program Overview Since it was launched in 1996, OnStar has relied on an analog wireless network to provide communication to and from OnStar-equipped vehicles. As part of an industry wide change in the North American wireless telecommunications industry, wireless carriers are transitioning to digital technology and will no longer support the analog wireless network beginning early Effective January 1, 2008, OnStar service in the United States and Canada will be available only through vehicles that are capable of operating on the digital network. Refer to Corporate Bulletin Number H for information about upgrading certain vehicles to digital service. Details were covered in both the November 2006 and December 2007 issues of TechLink, which are available in the Archives of the TechLink website. Vehicles eligible for an OnStar hardware upgrade are listed in this bulletin. Vehicle upgradeability can also be determined by typing the VIN into the field entitled "Determine VIN Hardware Functionality" on the OnStar Online Enrollment website, located in the sales or service workbench tab of GM GlobalConnect. Canadian Dealers can use a similar tool that is available within the OnStar Canada Online Enrollment site that can be accessed from the OnStar Brand Resources in GlobalConnect. Access to the sales and/or service workbench in the GM GlobalConnect website can be granted by the dealership s Partner Security Coordinator (PSC). If you are unsure who the PSC is, check with the Sales Manager. General Information 1. The first step is to verify if the OnStar account is active or not. This can be done by pressing the blue OnStar button and connecting to the OnStar call center. Analog only accounts are no longer active. Only digital upgraded accounts will be active. On Gen 6 digital systems, a clear, or "dark" LED may indicate that the OnStar system has been deactivated or may possibly have a no power/no communication condition. 2. If the account isn t active, the next step is to verify what version of OnStar module is in the vehicle. This can be done via the Tech 2 (Body>VCIM>Module ID Information>Module Information 2) or by using 3. A Generation 5 or older analog module can be diagnosed by following the original electronic Service Information developed for the model year of the vehicle. Note: If the customer has an old analog module, the vehicle can be repaired by replacing the module, but the customer cannot have an active account without upgrading to a digital module. 4. Modules, antennas, brackets, and other equipment are in the same location, whether original analog production or digital upgrade. 5. An upgraded vehicle may also have a new vehicle communication interface module (VCIM) bracket. If it does, order the new bracket when replacing the bracket. Don t order the original bracket. The kit may also include a small wiring jumper cable. If it does, this jumper will be required for a new module replacement. Do not discard. 6. After replacing the VCIM, it is essential to configure the new OnStar system. Failure to configure the system will result in an additional customer visit for repair. DO NOT press and hold the white dot or phone button on the keypad as it will not reset this version of the OnStar system and may result in a DTC being set. Use of the TIS2WEB and SPS applications, along with the Tech2, are required in order to perform the VCIM configuration and setup procedure for this vehicle. The configuration and set-up procedure is now a two-step process which enables an automated activation by the OnStar Center, without a button press by the technician to the OnStar Call Center. Vehicles Built with Upgradeable OnStar System Analog Modules

3 2000 Model Year Code Brand Model Built with Hardware GMX220 Buick LeSabre Gen 2 GMX210 Chevrolet Impala Gen 2 GMX230 Chevrolet Monte Carlo Gen 2 GMX310 Pontiac Bonneville Gen Model Year Code Brand Model Built with Hardware GMX220 Buick LeSabre Gen 2/3 GMX210 Chevrolet Impala Gen 2/3 GMX230 Chevrolet Monte Carlo Gen 2/3 GMX160 Oldsmobile Aurora Gen 2/3 GMX310 Pontiac Bonneville Gen 2/ Model Year Code Brand Model Built with Hardware GMX220 Buick LeSabre Gen 4 GMX270 Cadillac DeVille Gen 4 E/K Cadillac Seville Gen4 GMX210 Chevrolet Impala Gen 4 GMX230 Chevrolet Monte Carlo Gen 4 GMT360 Chevrolet TrailBlazer Gen 4 GMT370 Chevrolet TrailBlazer EXT Gen 4 GMT360 GMC Envoy Gen 4 GMT370 GMC Envoy XL Gen 4 GMX160 Oldsmobile Aurora Gen 4 GMT360 Oldsmobile Bravada Gen 4 GMX170 Oldsmobile Intrigue Gen 4 GMX310 Pontiac Bonneville Gen Model Year Header Header Header Header W Buick Century Gen 4.5/4.6 GMX220 Buick LeSabre Gen 5.1/5.2 W Buick Regal Gen 4.5/4.6 GMT257 Buick Rendezvous Gen 5.1/5.2 GMX320 Cadillac CTS Gen 4.5/4.6 GMX320 Cadillac CTS Gen 5.2 GMX270 Cadillac DeVille Gen 4.5/4.6 GMX270 Cadillac DeVille Gen 5.2 GMT 820 Cadillac Escalade Gen 5.1/5.2 GMT830 Cadillac Escalade ESV Gen 5.1/5.2 GMT806 Cadillac Escalade EXT Gen 5.1/5.2

4 E/K Cadillac Seville Gen 4.5/4.6 E/K Cadillac Seville Gen 5.2 GMT805 Chevrolet Avalanche Gen 5.1/5.2 J Chevrolet Cavalier Gen 5.1/5.2 GMT610 Chevrolet Express Gen 5.1/5.2 GMX210 Chevrolet Impala Gen 4.5/4.6 GMX210 Chevrolet Impala Gen 5.2 GMX230 Chevrolet Monte Carlo Gen 4.5/4.6 GMX230 Chevrolet Monte Carlo Gen 5.2 GMT800 Chevrolet Silverado Gen 5.1/5.2 GMT830 Chevrolet Suburban Gen 5.1/5.2 GMT820 Chevrolet Tahoe Gen 5.1/5.2 GMT360 Chevrolet TrailBlazer Gen 5.1/5.2 GMT370 Chevrolet TrailBlazer EXT Gen 5.1/5.2 GMT200 Chevrolet Venture Gen 5.1/5.2 GMT360 GMC Envoy Gen 5.1/5.2 GMT360 GMC Envoy XL Gen 5.1/5.2 GMT610 GMC Savana Gen 5.1/5.2 GMT800 GMC Sierra/Denali Gen 5.1/5.2 GMT830 GMC Yukon XL/Denali XL Gen 5.1/5.2 GMT820 GMC Yukon/Denali Gen 5.1/5.2 GMT800 hummer H2 Gen 5.1/5.2 GMT370 Isuzu Ascender EXT Gen 5.1/5.2 GMX160 Oldsmobile Aurora Gen 5.1/5.2 GMT360 Oldsmobile Bravada Gen 5.1/5.2 GMT200 Oldsmobile Silhouette Gen 5.1/5.2 GMT250 Pontiac Aztec Gen 5.1/5.2 GMX310 Pontiac Bonneville Gen 5.1/5.2 GMT200 Pontiac Montana Gen 5.1/5.2 J Pontiac Sunfire Gen 5.1/5.2 GMX357 Saturn Ion Gen 5.1/5.2 J-2902 Saturn LS/LW Gen 4.5/4.6 J-2902 Saturn LS/LW Gen 5.2 GMT315 Saturn Vue Gen 4.5/4.6 GMT315 Saturn Vue Gen 5.1/ Model Year Brand Model Built with Hardware Buick Century Gen 5.2 Buick LeSabre Gen 5.2 Buick Rainier Gen 5.2/6.0 Buick Regal Gen 5.2 Buick Rendezvous Gen 5.2/6.0 Cadillac CTS Gen 5.2

5 Cadillac DeVille Gen 5.2 Cadillac Escalade Gen 5.2/6.0 Cadillac Escalade EXT Gen 5.2/6.0 Cadillac Escalade ESV Gen 5.2/6.0 Cadillac Seville Gen 5.2 Cadillac SRX Gen 5.2 Cadillac XLR Gen 5.2 Chevrolet Avalanche Gen 5.2/6.0 Chevrolet Cavalier Gen 5.2 Chevrolet Colorado Gen 5.2 Chevrolet Express Gen 5.2 Chevrolet Impala Gen 5.2 Chevrolet Malibu Gen 5.2 Chevrolet Malibu (MAXX) Gen 5.2 Chevrolet Monte Carlo Gen 5.2 Chevrolet Silverado Gen 5.2/6.0 Chevrolet Suburban Gen 5.2/6.0 Chevrolet Tahoe Gen 5.2/6.0 Chevrolet TrailBlazer Gen 5.2/6.0 Chevrolet TrailBlazer EXT Gen 5.2/6.0 Chevrolet Venture Gen 5.2 GMC Canyon Gen 5.2 GMC Envoy Gen 5.2/6.0 GMC Envoy XL Gen 5.2/6.0 GMC Envoy XUV Gen 5.2/6.0 GMC Savana Gen 5.2 GMC Sierra/Denali Gen 5.2/6.0 GMC Yukon/Denali Gen 5.2/6.0 GMC Yukon XL/Denali XL Gen 5.2/6.0 Hummer H2 Gen 5.2/6.0 Isuzu Ascender Gen 5.2/6.0 Isuzu Ascender EXT Gen 5.2/6.0 Oldsmobile Bravada Gen 5.2 Oldsmobile Silhouette Gen 5.2 Pontiac Aztec Gen 5.2/6.0 Pontiac Bonneville Gen 5.2 Pontiac Grand Prix Gen 5.1 Pontiac Montana Gen 5.2 Pontiac Sunfire Gen 5.2 Saturn Ion Gen 5.2 Saturn LS Gen 5.2 Saturn LW Gen 5.2 Saturn Vue Gen 5.2

6 2005 Model Year Code Brand Model Built with Hardware MS2000 Buick Century Gen 5.2 GMX320 Cadillac CTS Gen 5.3/6.0 GMT265 Cadillac SRX Gen 5.3/6.0 GMX295 Cadillac STS Gen 5.3 GMX215 Cadillac XLR Gen 5.3 J Chevrolet Cavalier Gen 5.3 GMX001 Chevrolet Cobalt Gen 5.3 GMX245 Chevrolet Corvette Gen 5.3 GMT191 Chevrolet Equinox Gen 5.3 GMX380 Chevrolet Malibu Gen 5.3 GMX380 Chevrolet Malibu MAXX Gen 5.3 GMT200 Chevrolet Venture Gen 5.3 GMX381 Pontiac G6 Gen 5.3 GMT200 Pontiac Montana Gen 5.3 GMX001 Pontiac Pursuit Gen 5.3 J Pontiac Sunfire Gen Model Year Code Brand Model Built with Hardware GMX295 Cadillac STS Gen 5.3 GMX001 Chevrolet Cobalt Gen 5.3 GMX245 Chevrolet Corvette Gen 5.3 GMX001 Pontiac Pursuit Gen 5.3 GMT192 Pontiac Torrent Gen 5.3 Note: 2007 Model Year Vehicles and Newer all have Digital OnStar Modules. OnStar Description and Operation This OnStar digital system consists of the following components: Vehicle Communication Interface Module (VCIM) OnStar button assembly Microphone Cellular antenna Navigation antenna Note: This system also interfaces with the factory installed vehicle audio system. Vehicle Communication Interface Module (VCIM) The vehicle communication interface module (VCIM) is a cellular device that allows the user to communicate data and voice signals over the national cellular network. Power is provided by a dedicated, fused B+ circuit. Ground is provided through the vehicle wiring harness attached to the module. The ignition state is determined by the VCIM through serial data messaging.

7 Dedicated circuits are used to connect the VCIM to a microphone, the button assembly, and to command the status LED. The VCIM communicates with the rest of the vehicle modules using the serial data bus. The module houses 2 technology systems, one to process GPS data, and another for cellular information. The cellular system 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. GPS satellites orbiting earth are constantly transmitting signals of their current location. The OnStar system uses the GPS signals to provide location on demand. The module also has the capability of activating the horn, initiating door lock/unlock, or activating the exterior lamps using the serial data circuits. These functions can be commanded by the OnStar Call Center per: a customer request. OnStar Button Assembly The OnStar button assembly may be part of the rearview mirror, or a separate, stand alone unit. The button assembly is comprised of 3 buttons and a status LED. The buttons are defined as follows: The answer/end call button, which is black with a white phone icon, allows the user to answer and end calls or initiate speech recognition. The blue OnStar call center button, which displays the OnStar logo, allows the user to connect to the OnStar call center. The emergency button, which displays a white cross with a red background, sends a high priority emergency call to the OnStar call center when pressed. The VCIM supplies 10 volts to the OnStar button assembly on the keypad supply voltage circuit. When pressed, each button completes a circuit across a resistor allowing a specific voltage to be returned to the VCIM on the keypad signal circuit. Depending upon the voltage range returned the VCIM is able to identify which button has been pressed. The OnStar status LED is located with the button assembly. The LED is green when the system is ON and operating normally. When the status LED is green and flashing, it is an indication that a call is in progress. When the LED is red, this indicates a system malfunction is present. In the event there is a system malfunction and the OnStar system is still able to make a call, the LED will flash red during the call. If the LED does not illuminate, this may indicate that the customers OnStar subscription is not active or has expired. Push the blue OnStar button to connect to an advisor who can then verify the account status. Each LED is controlled by the VCIM over dedicated LED signal circuits. Ground for the LED is provided by the wiring harness attached to the button assembly. OnStar Microphone The OnStar, or cellular microphone, can be a part of the rearview mirror assembly, or on some vehicle lines, a separate, stand alone unit. In either case, the VCIM supplies approximately 10 volts to the microphone on the cellular microphone signal circuit, and voice data from the user is sent back to the VCIM over the same circuit. A cellular microphone low reference circuit or a drain wire provides a ground for the microphone. Cellular and GPS Antennas

8 The vehicle will be equipped with one of the following types of antennas: Separate, standalone cellular and navigation (GPS) antennas. A combination cellular and navigation (GPS) antenna, which brings the functions of both into a single part. A cellular, GPS, and digital radio receiver (DRR) antenna, which also incorporates the functionality of the DRR satellite antenna (XM). The cellular antenna is the component that allows the OnStar system to send and receive data using electromagnetic waves by means of cellular technology. The antenna is connected at the base to a coax cable that plugs directly into the VCIM. The GPS antenna is used to collect the signals of the orbiting GPS satellites. Within the antenna is housed a low noise amplifier that allows for a more broad and precise reception of this data. The antenna is connected at the base to a coax cable that plugs directly into the VCIM. The cable also provides a path for DC current for powering the antenna. The OnStar Call Center also has the capability of communicating with the vehicle during an OnStar call 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, for as long as the module power is not removed. Actual GPS location may take up to 10 minutes to register in the event of a loss of power. Audio System Interface When the OnStar requires audio output, a serial data message is sent to the audio system to mute all radio functions and transmit OnStar originated audio. The OnStar audio is transmitted to the vehicle audio system by a dedicated signal circuit and a low reference circuit. The audio system will mute and an audible ring will be heard though the speakers if the vehicle receives a call with the radio ON. On some vehicles, the HVAC blower speed may be reduced when the OnStar system is active to aid in reducing interior noise. When the system is no longer active, the blower speed will return to its previous setting. OnStar Steering Wheel Controls Some vehicles may have a button on the steering wheel, that when pushed can engage the OnStar system. The button may be a symbol of a face with sound waves, or may say MUTE, or be a symbol of a radio speaker with a slash through it. By engaging the OnStar system with this feature, the user can interact with the system by use of voice commands. A complete list of these commands is supplied in the information provided to the customer. If the information is not available for reference, at any command prompt, the user can say "HELP" and the VCIM will return an audible list of available commands. The steering wheel controls consist of multiple momentary contact switches and a resistor network. 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. This produces a specific voltage value unique to the switch selected, to be interpreted by the radio or the body control module (BCM). OnStar Power Moding (DRX or Sleep Cycle) The OnStar system uses a unique sleep cycle to allow the system to receive cellular calls while

9 the ignition is in the OFF position and retained accessory power (RAP) mode has ended. A green status LED on the OnStar keypad normally indicates an active OnStar account. The OnStar system will stay powered up after ignition off for an extended time in order to allow for remote services like door unlock, horn honk, light flash, etcetera to take place as requested by the customer. Power cycle (also referred to as DRX) times vary depending on the generation of the OnStar system. Technicians may identify the OnStar system generation by using a Tech 2 and following this menu path: (Body>VCIM>Module ID Information>Module Information 2) or by accessing All Generation 6 digital systems are powered up continuously for 48 hours from ignition OFF. After 48 hours, the Generation 6 systems will enter a 9 minute OFF, 1 minute ON power cycle for an additional 72 hours. At the beginning and end of the 1 minute ON stage, you may or may not experience a short spike of current at the beginning and at the end. This allows for calls from OnStar to be received by the system. After 120 hours from ignition OFF, these systems will then completely power OFF. OnStar Module Expected Current Draw The expected current draw of the OnStar module in various ignition modes are as follows: Ignition ON to 400 ma Ignition OFF - 3 to 20 ma for 48 hours Ignition OFF to 0.8 ma after 48 hours (120 hours on specified vehicle communication platforms (VCPs)). Note: During extended voltage testing for battery parasitic draw, it is possible to observe a voltage spike caused by the following: - A cellular registration call that was triggered by the local cellular system. - The OnStar system has set a monthly trigger for a vehicle data upload call for the OnStar Vehicle Diagnostic upload. OnStar System States of Readiness The OnStar system will use the following 4 states of readiness, depending upon the type of cellular market the vehicle is in when the ignition is turned OFF. High power Low power Sleep Digital standby The high power state is in effect whenever the ignition is in the ON or RUN position, retained accessory power (RAP) is enabled, and/or the OnStar system is sending or receiving calls or when the system is performing a remote function. The low power state is in effect when the OnStar system is idle with the ignition in the ON or RUN position, or with RAP enabled. The sleep state is entered after the vehicle has been shut OFF and the RAP has timed out. At a predetermined time recorded within the VCIM, the system re-enters the low power state to listen for a call from the OnStar Call Center for 1 minute. After this interval, the system will again return to the sleep state for 9 minutes. If a call is sent during the 1 minute interval, the OnStar system will receive the call and immediately go into the high power mode to perform

10 any requested functions. If a call is not received during the 1 minute interval, the system will go back into the sleep mode for another 9 minutes. This process will continue for up to 48 hours, after which the OnStar system will turn OFF until the ignition is turned to the ON or RUN position. The digital standby power state is entered after the vehicle has been shut off and the RAP has timed out while in a digital cellular area. When in digital standby mode, the OnStar module is able to perform all remote functions as commanded by an OnStar advisor at any time, for a continuous 48 hours. After 48 hours, the OnStar module will go into sleep mode until a wake up signal from the vehicle is seen by the CIM. If the OnStar module loses the digital cellular signal it will revert to analog mode and follow the standard sleep state (9 minutes OFF, 1 minute standby) based on the time of the GPS signals, this will continue until a digital cellular signal is again received. If the OnStar system loses battery power while the system is in a standby or sleep mode, the system will remain OFF until battery power is restored and the ignition is turned to the ON or RUN position. Deactivated OnStar Accounts In the event that a customer has not upgraded their vehicle to a digital system, the account has been deactivated. The customers have been previously notified of the steps required to upgrade their vehicles. After the OnStar account has been deactivated, customers will experience the following: The OnStar status LED will not illuminate The OnStar system will NOT attempt to connect to the OnStar Call Center in the event of a collision or if the vehicle's front air bags deploy for any other reason. An emergency button press will result in a demo message being played, indicating the service has been deactivated and needs to be upgraded. An OnStar Call Center button press WILL NOT connect the vehicle with OnStar. The vehicle must be upgraded to reactivate the account. The customer will hear a demo message stating that there is not a current OnStar subscription for the vehicle. The message will also instruct the customer how to upgrade and reactivate services. 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 will result in cellular connection failure messages and the inability to connect to the number dialed. Note: For deactivated vehicles, a no connect response should be considered normal system operation. Further diagnosis and subsequent repair is only necessary should the customer elect to become an active OnStar subscriber and upgrade the account subscription. OnStar Cellular, GPS, and Diagnostic Limitations The proper operation of the OnStar System is dependent on several elements outside the components integrated into the vehicle. These include the National Cellular Network Infrastructure, the cellular telephone carriers within the network, and the GPS. The cellular operation of the OnStar system may be inhibited by factors such as the users range from a digital cellular tower, the state of the cellular carrier s equipment, and the location where the call is placed. Making an OnStar key press in areas that lack sufficient cellular coverage or have a temporary equipment failure will result in either the inability of a call to complete with a data transfer or the complete inability to connect to the OnStar Call Center. The OnStar system may also experience connection issues if the identification numbers for the module, station identification number (STID), electronic serial number (ESN) or manufacturers electronic ID (MEID), are not recognized by the cellular carriers local signal receiving towers.

11 The satellites that orbit earth providing the OnStar system with GPS data have almost no failures associated with them. In the event of a no GPS concern, the failure will likely lie with the inability of the system to gain GPS signals because of its location, i.e. in a parking structure, hardware failure, or being mistaken with an OnStar call which has reached the Call Center without vehicle data. During diagnostic testing of the OnStar system, the technician should ensure the vehicle is located in an area that has a clear unobstructed view of the open sky, and preferably, an area where digital cellular calls have been successfully placed. These areas can be found by successfully making an OnStar keypress in a known good OnStar equipped vehicle and confirming success with the OnStar Call Center advisor. Such places can be used as a permanent reference for future OnStar testing. Mobile Identification Number and Mobile Directory Number The vehicle communication interface module (VCIM) utilizes 2 numbers for cellular device identification, call routing and connection. They are: A mobile identification number (MIN) A mobile directory number (MDN) Note: The MIN represents the number used by the cellular carrier for call routing purposes. The MDN represents the number dialed to reach the cellular device. Diagnostic Information Symptoms - Cellular Communication The following steps must be completed before using the symptom table. 1. Perform the Diagnostic System Check - Vehicle, before using the Symptom Tables in order to verify that the following are true: - There are no DTCs set. - The control modules can communicate via the serial data link. 2. Review the system operation in order to familiarize yourself with the system functions. Refer to Radio/Audio System Description and Operation in SI. Diagnostic Starting Point - Displays and Gages Begin the displays and gages system diagnosis with Diagnostic System Check - Vehicle or the audible warning system diagnosis with Diagnostic System Check - Vehicle. The Diagnostic System Check will provide the following information: The identification of the control modules which command the system The ability of the control modules to communicate through the serial data circuit The identification of any stored diagnostic trouble codes (DTCs) and their status The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located. Visual/Physical Inspection Perform the following visual inspections;

12 Inspect for aftermarket devices which could affect the operation of the Radio/Audio System. Refer to Checking Aftermarket Accessories in SI. Inspect the easily accessible and visible system components for obvious damage or conditions which could cause the symptom. Intermittent Conditions Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in SI. Symptom List Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom. No Global Positioning System (GPS) Reception OnStar Audio Malfunction OnStar Button LED Malfunction OnStar Button Malfunction OnStar Call Center Remote Function Requests Malfunction OnStar Global Positioning System (GPS) Data Not Current or Inaccurate OnStar Microphone Malfunction OnStar Steering Wheel Control Functions Malfunction OnStar Voice Recognition Malfunction Unable to Contact OnStar Call Center Diagnostic Trouble Codes Upgraded vehicles will utilize the DTCs in the following table: Upgraded Vehicle Diagnostic Trouble Codes GMLAN Diagnostic Trouble Code Class 2 Diagnostic Trouble Code Symptom Byte (GMLAN Only) Value (HEX) U0073 N/A $00 C U0140 N/A $00 C U0155 N/A $00 C U0184 N/A $00 C U0151 N/A $00 C Description Single Wire GMLAN Control Module Communication Bus Off Supervised Lost Communication With Body Control Module (BCM) Supervised Lost Communication With Instrument Panel Cluster (IPC) Control Module Supervised Lost Communication With Radio Supervised Lost Communication With

13 Restraints Control Module N/A U U1255 $00 -- Loss of Serial Communication for Class 2 Devices N/A U1016 $00 -- Loss of Serial Data with PCM N/A U1064 $00 -- Loss of Serial Data with BCM N/A U1088 $00 -- Loss of Serial Data with SDM N/A U1096 $00 -- Loss of Serial Data with IPC N/A U1128 $00 -- Loss of Serial Data with Radio N/A U1300 $00 -- Class 2 Short to Ground N/A U1301 $00 -- Class 2 Short to Battery N/A B1327 $00 -- Source/Battery Voltage Low U2100 N/A $00 -- CAN Bus Communication Failure U2103 N/A $00 -- Fewer Controllers on Bus Than Programmed B1000 B1000 $ Electronic Control Unit (ECU) Performance General Checksum Failure B1000 B1000 $ Electronic Control Unit (ECU) Performance General Memory Failure B1000 B1000 $ Electronic Control Unit (ECU) Performance Supervision Software Failure Electronic Control Unit (ECU) Performance B1000 B1000 $ B1000 B1000 $3B B B1000 B1000 $3C C Bluetooth Failure (Internal Self Test Failure) Electronic Control Unit (ECU) Performance GPS Self Test Failure (Internal Self Test Failure) Electronic Control Unit (ECU) Performance Loss of Communication with GPS (Internal

14 B1001 B1001 $ B2455 B2455 $04 A B2462 B2483 $02 A B2462 B2484 $04 A B2470 B2470 $04 A B2476 B2476 $04 A B2476 B2482 $59 A Communications Failure) Option Configuration Error Vehicle Configuration Not Programmed Cellular Phone Microphone Circuit Malfunction Open Circuit GPS Antenna Malfunction Short to Ground GPS Antenna Malfunction Open Circuit Cellular Phone Antenna Circuit Malfunction Open Circuit Cellular Phone Select Service Switch Malfunction Open Circuit Cellular Phone Select Service Switch Malfunction Stuck Button DTC U1000 and U1255 Circuit/System Description Modules connected to the Class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for State of Health monitoring. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. When a module does not associate an identification number with at least one critical parameter within 5 seconds of beginning serial data communication, DTC U1000 or U1255 DTC is set. When more than one critical parameter does not have an identification number associated with it, the DTC will only be reported once. The Class 2 serial data communications circuit on this vehicle are in a hybrid ring and star configuration. Each module on the ring has 2 serial data circuits connected to it, except the following modules which have only 1 serial data circuit connected them: Audio amplifier Driver door module (DDM)

15 Driver door switch assembly (DDSA) Front passenger door module (FPDM) Left rear door module (LRDM) Memory seat module (MSM) Radio antenna module (listed as remote function actuation in scan tool display) Rear integration module (RIM) Right rear door module (RRDM) Theft deterrent module (TDM) TV antenna module Vehicle communication interface module (VCIM) The star has 4 splice packs: SP200 located in the left side of the instrument panel, near the steering column, taped to the instrument panel harness SP201 located in the center of the instrument panel, near the radio SP300 located in the left side middle of the passenger compartment, taped to the body harness, near the carpet seam SP303 located in the right rear of the passenger compartment, taped to the body harness, approximately 24 cm (9.5 in) from the fuse block - right rear. Refer to Data Communication Schematics in SI. The following modules, components, and splice packs are connected to the ring portion of the class 2 serial data circuit: Dash integration module (DIM) Electronic brake control module (EBCM) Engine control module (ECM) Inflatable restraint sensing and diagnostic module (SDM) Instrument panel cluster (IPC) HVAC control module Radio Rear integration module (RIM) Vehicle communication interface module (VCIM) OR Communication interface module (CIM) SP200 SP201 SP300 SP303 The following modules, components, and splice pack are connected to the star portion of the class 2 serial data circuit: SP300 Audio amplifier Driver door module (DDM)

16 Driver door switch assembly (DDSA) Memory seat module (MSM) Left rear door module (LRDM) AND SP303 Antenna module Front passenger door module (FPDM) Rear integration module (RIM) Right rear door module (RRDM) Theft deterrent module (TDM) Vehicle communication interface module (VCIM). Refer to Data Communication Schematics and Data Link Communications Description and Operation in SI. Conditions for Running the DTC Voltage supplied to the module is in the normal operating voltage range of 9-16 volts. DTCs B1327, B1328, U1300, U1301, U1305 are not set as current. The vehicle power mode requires serial data communication to occur. Conditions for Setting the DTC A message containing a critical operating parameter has not been received within the last 5 seconds after establishing class 2 serial data communication. Action Taken When the DTC Sets The module uses a default value for the missing parameter. Conditions for Clearing the DTC A current DTC clears when the malfunction is no longer present. A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. Diagnostic Aids When a malfunction such as an open fuse to a module occurs while modules are communicating, a DTC U Loss of XXX Communications is set current. When the modules stop communicating the current DTC U Loss of XXX Communications is cleared but the history DTC remains. When the modules begin to communicate again, the module with the open fuse will not be learned by the other modules so U1000 or U1255 is set current by the other modules. If the malfunction occurs when the modules are not communicating, only U1000 or U1255 is set. Test Description The numbers below refer to the step numbers on the diagnostic table. 1. A DTC U U1254 Lost Communications with XXX with a history status may indicate

17 the cause of U1000 or U The modules not communicating are the likely cause of U1000 or U1255. The modules that are available on the class 2 serial data circuit are listed in the Circuit Description. 6. The module which was not communicating due to a poor connection to the class 2 serial data circuit may have set DTC U U1254 Lost Communications with XXX for those modules that it was monitoring. 9. The modules which can communicate indicate the module which cannot communicate. You must clear the serial data communication DTCs from these modules to avoid future misdiagnosis. 12. If all modules are communicating, the module which set U1000 or U1255 may have done so due to some other condition. 14. The module which set U1000 or U1255 is the likely cause of the malfunction. Step Action Yes No Schematic Reference: Data Link References and Control Module References Connector End View Reference: Master Electrical Component List and Inline Harness Connector End Views in Wiring Systems Circuit Testing and Repairs Reference: Circuit Testing, Wiring Repairs and Testing for Intermittent Conditions and Poor Connections in Wiring Systems Module Replacement Reference: Repair Instruction, and Programming and Setup in Control Module References Install a scan tool. 2. Turn ON the ignition, with the engine OFF. 3. Record the DTCs set by each module. If using a Tech 2, use the Class 2 DTC Check feature to determine which modules have DTCs set. Did you record any DTCs in the range of U1001-U1254 with a history status? 1. Attempt to communicate with each module on the Class 2 serial data circuit. If using a Tech 2, obtain this information using the Class 2 Message Monitor feature. 2. Observe and record all of the modules that are communicating on the Class 2 serial data circuit. 3. Compare the list of modules which are communicating to the list given in the Circuit/System Description. Go to Diagnostic Trouble Code (DTC) List Go to Step 2 Does any module on the Class 2 serial data circuit not communicate? Go to Step 3 Test the following circuits of the module that is not communicating for an open or short to ground: Go to Step 12

18 3 4 5 The battery positive voltage supply circuits The switched battery positive supply circuits The battery positive voltage output circuits The ignition voltage input circuits The ignition voltage output circuits Did you find and correct the condition? 1. Turn OFF the ignition. 2. Test the ground circuits of the module that is not communicating for an open. Go to Step 8 Did you find and correct the condition? Go to Step 8 Important: Inspect all connectors in the serial data communications circuit. Test the Class 2 serial data circuits of the module that is not communicating for an open. Did you find and correct the condition? Go to Step 8 Test the harness connector of the module that is not communicating for poor connections and terminal tension at the following circuits: Go to Step 4 Go to Step 5 Go to Step Battery positive voltage input Switched battery positive voltage supply Battery positive voltage output Ignition voltage input Ignition voltage output Ground Class 2 serial data Did you find and correct the condition? Important: Perform the module programming or setup procedure if required. Replace the module that is not communicating. Go to Step 8 Go to Step Did you complete the replacement? Go to Step Turn ON the ignition, with the engine OFF. 2. Select the Display DTCs function for the module which was not communicating. Does the scan tool display any DTCs which do not begin with a "U"? Clear the DTCs with a scan tool. Go to Control Module References for Diagnostic System Check - Vehicle Go to Step 9 Did you complete the action? Go to Step 10 --

19 Select the Display DTCs function for the modules which had U1000 or U1255 set as a current DTC. Does the scan tool display any DTCs which do not begin with a "U"? Clear the DTCs with a scan tool. Go to Control Module References for Diagnostic System Check - Vehicle Go to Step 11 Did you complete the action? System OK -- Did you record any other DTCs for the modules which has U1000 or U1255 set as a current DTC? 1. Turn OFF the ignition for 90 seconds. 2. Turn ON the ignition, with the engine OFF. 3. Select the Display DTCs function Go to Control Module References for Diagnostic System Check - Vehicle Does the scan tool display U1000 or U1255 as a current DTC? Go to Step 14 Replace the module which had U1000 or U1255 set as a current DTC. Go to Step 13 Go to Diagnostic Aids Did you complete the replacement? System OK -- DTC U1001 and U1254 Circuit/System Description Modules connected to the Class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for State of Health monitoring. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module's Node Alive message. Each module on the class 2 serial data circuit which is powered and performing functions that require detection of a communications malfunction is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a DTC U1XXX where XXX is equal to the 3-digit identification number is set. The control module ID number list below provides a method for determining which module is not communicating. A module with a class 2 serial data circuit malfunction or which loses power during the current ignition cycle will have a Loss of Communication DTC set by other modules that depend on information from that failed module. The modules that can communicate will set a DTC indicating the module that cannot communicate. Control Modules and Devices - Description and Identification Number Control Module Description ID number Engine Control Module (ECM) 016 Electronic Brake Control Module (EBCM) 040

20 Dash Integration Module (DIM) 064 Rear Integration Module (RIM) Inflatable Restraint Sensing and Diagnostic Module (SDM) 088 Instrument Panel Cluster (IPC) 096 Radio 128 Audio Amplifer 129 Radio Antenna Module 134 TV Antenna Module 135 Cellular Telephone 144 Vehicle Communication Interface Module (VCIM) 97 HVAC Control Module 153 Driver Door Module (DDM) 160 Front Passenger Door Module (FPDM) 161 Left Rear Door Module (LRDM) 162 Right Rear Door Module (RRDM) 163 Driver Door Switch Assembly (DDSA) 164 Theft Deterrent Control Module (TDM) 192 Memory Seat Module (MSM) 166 Diagnostic Order When more than one Loss of Communication DTC is set in either one module or in several modules, diagnose the DTCs in the following order: 1. Current DTCs before history DTCs unless told otherwise in the diagnostic table. 2. The DTC which is reported the most times. 3. From the lowest number DTC to the highest number DTC. Conditions for Running the DTC The following DTCs do not have a current status: B1327 B1328 U1300 U1301 U1305 AND The vehicle power mode requires serial data communication to occur. Conditions for Setting the DTC A node alive message has not been received from a module with a learned identification number within the last 5 seconds. Action Taken When the DTC Sets The module uses a default value for the missing parameter.

21 Conditions for Clearing the DTC A current DTC clears when the malfunction is no longer present. A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. Diagnostic Aids When multiple Loss of Communication DTCs are set concurrently, the cause is likely to be 2 opens in the ring portion of the class 2 serial data circuit. Use the Control Modules and Devices - Description and Identification Number table in order to determine which modules are not communicating. Use the class 2 serial data circuit schematic in order to determine the location of the opens. Test Description The number below refers to the step number on the diagnostic table. 6. The module which was not communicating on the Class 2 serial data circuit may have set Loss of Communication DTCs for those modules that it was monitoring. Step Action Yes No Schematic Reference: Data Link References and Control Module References Connector End View Reference: Master Electrical Component List and Inline Harness Connector End Views in Wiring Systems Circuit Testing and Repairs Reference: Circuit Testing, Wiring Repairs and Testing for Intermittent Conditions and Poor Connections in Wiring Systems Module Replacement Reference: Repair Instruction, and Programming and Setup in Control Module References Important: Use the Control Modules and Devices - Description and Identification Number table to determine which module is not communicating. Test the following circuits of the module that is not communicating for an open or short to ground: 1 The battery positive voltage input circuits The battery positive voltage output circuits The switched battery positive voltage circuits The ignition voltage input circuits The ignition voltage output circuits Did you find and correct the condition? 1. Turn OFF the ignition. 2. Test the ground circuits of the Go to Step 6 Go to Step 2

22 2 3 module that is not communicating for an open. Did you find and correct the condition? Go to Step 6 Go to Step 3 Test the Class 2 serial data circuits of the module that is not communicating for an open. Did you find and correct the condition? Go to Step 6 Go to Step 4 Test the harness connector of the module that is not communicating for poor connections and terminal tension at the following circuits: 4 Battery positive voltage input Battery positive voltage output Switched battery positive voltage supply Ignition voltage input Ignition voltage output Ground Class 2 serial data Did you find and correct the condition? Important: Perform the module programming or setup procedure if required. Go to Step 6 Go to Step Replace the module that is not communicating. Did you complete the replacement? Go to Step Turn ON the ignition, with the engine OFF. 2. Select the Display DTCs function for the module which was not communicating. Does the scan tool display any DTCs which do not begin with a "U"? Select the Display DTCs function for the modules which had the Loss of Communications DTC set. Does the scan tool display any DTCs which do not begin with a "U"? Clear the DTCs with a scan tool. Continue diagnosing or clearing the DTCs from all modules. Did you complete the action Go to Control Module References for Diagnostic System Check - Vehicle Go to Step 7 Go to Control Module References for Diagnostic System Check - Vehicle Go to Step 8 System OK Go to Control Module References for Diagnostic System Check - Vehicle

23 DTC U0073 or U2100 DTC Descriptors DTC U : Control Module Communication Bus Off DTC U : ECU HS Bus Off DTC U : ECU LS Bus Off DTC U : Controller Area Network (CAN) Bus Communication DTC U : Controller Area Network (CAN) Bus Communication Circuit/System Description The serial data circuits are serial data buses used to communicate information between the control modules. The serial data circuits also connect directly to the data link connector (DLC). Conditions for Running the DTCs Supply voltage at the modules are in the normal operating range. The vehicle power mode requires serial data communications. Conditions for Setting the DTC The module setting the DTC has attempted to establish communications on the serial data circuits more than 3 times. Action Taken When the DTCs Sets The module suspends all message transmission. The module uses default values for all parameters received on the serial data circuits. The module inhibits the setting of all other communication DTCs. Conditions for Clearing the DTC A current DTC clears when the malfunction is no longer present. A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction. Circuit/System Verification Refer to Data Link References to determine which serial data system is used for a specific module. This DTC cannot be retrieved with a current status. Diagnosis is accomplished using the following symptom procedures: Scan Tool Does Not Communicate with High Speed GMLAN Device in SI.

24 OR Scan Tool Does Not Communicate with Low Speed GMLAN Device in SI. DTC U U0184 Circuit Description Modules connected to the GMLAN serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on the GMLAN serial data circuit. When the module detects one of the following conditions on the GMLAN serial data circuit, a DTC will set. Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on the GMLAN serial data circuit. Conditions for Setting the DTCs Diagnostic algorithms are designed so that a single point failure within a particular node shall result in a single DTC/FTB combination being set. Any recognized faults shall generate one DTC. Recognized faults may include but are not limited to the following: Open or shorted condition on an I/O Circuit outside of normal operation of that circuit. Erratic signal of a circuit, outside of normal operation, which can be readily and repeatedly recognized as erratic. A condition, outside of normal operation, which causes a customer perception of a performance problem. A condition whether hardware or data link error, which causes a device to operate in a default or fail soft mode. A condition which changes or limits system performance. Network supervision/signal supervision errors. ECU Internal errors. Criteria determined by legislation. An initialization or shutdown self-test shall be performed and may include but is not limited to the following: RAM check ROM/EEPROM/Flash check I/O check Any faults detected during the initialization self-test shall generate a DTC. All nodes also continuously perform a self-test while in an active state. DTCs and their associated telltales will set as a result of unprogrammed or unlearned information. DTCs, which are defined for system configuration (e.g. Vehicle Option Content not programmed) do not support the history status bit (set =0). Warning indicator bit is also set, when applicable, while this DTC is present.

25 Action Taken When the DTCs Sets The module suspends all message transmission. The module uses default values for all parameters received on the serial data circuits. The module inhibits the setting of all other communication DTCs. Conditions for Clearing the DTC A current DTC clears when the malfunction is no longer present. A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction. Circuit/System Verification Refer to Data Link References to determine which serial data system is used for a specific module. The DTCs cannot be retrieved with a current status. Diagnosis is accomplished using the following symptom procedures: Scan Tool Does Not Communicate with High Speed GMLAN Device in SI. OR Scan Tool Does Not Communicate with Low Speed GMLAN Device in SI. DTC U1300, U1301, or U1305 Circuit Description Modules connected to the Class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on the Class 2 serial data circuit about once every 2 seconds. When the module detects one of the following conditions on the Class 2 serial data circuit for approximately 3 seconds, the setting of all other Class 2 serial communication DTCs is inhibited and a DTC will set. Diagnostic Fault Information DTC U1300 U1301 Conditions for Running the DTCs Condition Low voltage on the Class 2 serial data circuit High voltage on the Class 2 serial data circuit U1305* Either high or low voltage on the Class 2 serial data circuit. *Some modules will set DTC U1305 if they are not capable of distinguishing between a short to battery voltage or ground. Voltage supplied to the module is in the normal operating voltage range.