Circuit/System Verification
If this DTC is retrieved as a current DTC, replace the module that set the DTC.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for the non-communicating module replacement, setup, and programming
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BCM replacement, setup, and programming
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.
Reference Information
Schematic Reference
- «Data Communication Schematics»(ref-278002-S04537425502008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000)
Connector End View Reference
- «Data Communication Connector End Views»(ref-278002-S06109933032008012100000)
- «Master Electrical Component List»(ref-278021-S00742900972008012100000)
Electrical Information Reference
- «Circuit Testing»(ref-278019-S01379251932008012100000)
- «Connector Repairs»(ref-278019-S06982211772008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-278019-S21810776732008012100000)
- «Wiring Repairs»(ref-278019-S25320832652008012100000)
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-278019-S39351135082008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000) for replacement, setup, and programming
Schematic Reference
- «Body Control System Schematics»(ref-278002-S22677490482008012100000)
- «Data Communication Schematics»(ref-278002-S04537425502008012100000)
Connector End View Reference
Master Electrical Component List
Electrical Information Reference
- «Circuit Testing»(ref-278019-S01379251932008012100000)
- «Connector Repairs»(ref-278019-S06982211772008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-278019-S21810776732008012100000)
- «Wiring Repairs»(ref-278019-S25320832652008012100000)
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for module replacement, setup, and programming
Schematic Reference
- «Body Control System Schematics»(ref-278002-S22677490482008012100000)
- «Data Communication Schematics»(ref-278002-S04537425502008012100000)
Connector End View Reference
Master Electrical Component List
Electrical Information Reference
- «Circuit Testing»(ref-278019-S01379251932008012100000)
- «Connector Repairs»(ref-278019-S06982211772008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-278019-S21810776732008012100000)
- «Wiring Repairs»(ref-278019-S25320832652008012100000)
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for module replacement, setup, and programming
- 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.
Schematic Reference
- «Data Communication Schematics»(ref-278002-S04537425502008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000)
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-278019-S39351135082008012100000)
- «Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement»(ref-278027-S29694889382008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000) for module replacement, setup, and programming.
Symptoms - Data Communications
| IMPORTANT | The following steps must be completed before using the symptom tables. |
- Perform the «Diagnostic System Check - Vehicle»(ref-278018-S19353494792008012100000) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data links.
- Review the system operation in order to familiarize yourself with the system functions. Refer to «Data Link Communications Description and Operation»(ref-278002-S03063615792008012100000) .
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .
Schematic Reference
Data Communication Schematics
Connector End View Reference
Data Communication Connector End Views
Electrical Information Reference
- «Circuit Testing»(ref-278019-S01379251932008012100000)
- «Connector Repairs»(ref-278019-S06982211772008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-278019-S21810776732008012100000)
- «Wiring Repairs»(ref-278019-S25320832652008012100000)
Perform the Diagnostic Repair Verification after completing the repair.
Schematic Reference
- «Data Communication Schematics»(ref-278002-S04537425502008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000)
Connector End View Reference
Master Electrical Component List
Electrical Information Reference
- «Circuit Testing»(ref-278019-S01379251932008012100000)
- «Connector Repairs»(ref-278019-S06982211772008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-278019-S21810776732008012100000)
- «Wiring Repairs»(ref-278019-S25320832652008012100000)
Perform the Diagnostic Repair Verification after completing the repair.
- «GMLAN Wiring Repairs»(ref-278019-S39351135082008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000) for module replacement, setup, and programming
Schematic Reference
- «Data Communication Schematics»(ref-278002-S04537425502008012100000)
- «Control Module References»(ref-278020-S09054666032008012100000)
Connector End View Reference
Master Electrical Component List
Electrical Information Reference
- «Circuit Testing»(ref-278019-S01379251932008012100000)
- «Connector Repairs»(ref-278019-S06982211772008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-278019-S21810776732008012100000)
- «Wiring Repairs»(ref-278019-S25320832652008012100000)
Perform the Diagnostic Repair Verification after completing the repair.
- «Control Module References»(ref-278020-S09054666032008012100000) for module replacement, setup, and programming
- «GMLAN Wiring Repairs»(ref-278019-S39351135082008012100000)
Data Link References
This table identifies which serial data link that a particular module uses for in-vehicle data transmission. Some modules may use more than one data link to communicate. Some modules may have multiple communication circuits passing through them without actively communicating on that data link. This table is used to assist in correcting a communication malfunction. For the description and operation of these serial data communication circuits refer to Data Link Communications Description and Operation .
| Control Module | Data Link Type | Diagnostic Procedure |
|---|---|---|
| Schematic Reference: Data Communication Schematics | ||
| Amplifier | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Auxiliary Body Control Module (XBCM) (Export only) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Auxiliary HVAC Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Body Control Module (BCM) | High Speed GMLAN Low Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Communication Interface Module (OnStar), w/UE1 | High Speed GMLAN - pass through only Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Digital Radio Receiver (DRR), w/U2K | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Driver Door Switch (DDS) | Low Speed GMLAN Local Interconnect Network (LIN) | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Electronic Brake Control Module (EBCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Electronic Suspension Control Module (ESCM), F45, F55 | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Engine/Powertrain Control Module (ECM/PCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Front and Rear Object Alarm Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| HVAC Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Inside Rearview Mirror | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Instrument Panel Cluster (IPC) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Inflatable Restraint Sensing and Diagnostic Module (SDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Memory Seat Module (MSM)/Driver Position Module (DPM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Passenger Door Switch (PDS) | Low Speed GMLAN Local Interconnect Network (LIN) | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Passenger Presence System (PPS) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Radio | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Rear Heated/Vented Seat Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Remote Function Actuator (RFA) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Theft Deterrent Module (TDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Transmission Control Module (TCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
Data Link References
Scheme 28
| Callout | Component Name |
|---|---|
| Preliminary Procedures: Remove the inflatable restraint module. Refer to Inflatable Restraint Instrument Panel Module Replacement . | |
| 1 | Auxiliary Body Control Module Procedure Press on the tabs to release the auxiliary body control module. Disconnect the electrical connectors. Reprogram the auxiliary body control module if replaced. Refer to Control Module References . |
Auxiliary Body Control Module Replacement
Scheme 29
| Callout | Component Name |
|---|---|
| Preliminary Procedure: Remove the knee bolster. Refer to Knee Bolster Replacement (without RPO SLT) or Knee Bolster Replacement (with RPO SLT) | |
| 1 | Body Control Module Tip: Remove the BCM cover. Disconnect the electrical connectors. Press on the tabs to release the body control module. If a replacement module is installed, program the module. Refer to Control Module References . |
Body Control Module Replacement
Scheme 30
| Callout | Component Name |
|---|---|
| Preliminary Procedure Remove the knee bolster panel. Refer to Knee Bolster Replacement (without RPO SLT) or Knee Bolster Replacement (with RPO SLT) . Remove the instrument panel driver knee bolster deflector. Refer to Instrument Panel Driver Knee Bolster Deflector Replacement (without RPO SLT) or Instrument Panel Driver Knee Bolster Deflector Replacement (with RPO SLT) . | |
| 1 | Front Floor Heater Duct Retainer |
| 2 | Body Control Module Bracket Screws (Qty: 3) NOTE: Refer to Fastener Notice . Tighten: 2 N.m (18 lb in) |
| 3 | Body Control Module Bracket Assembly |
| NOTE |
|---|
| Refer to Fastener Notice . |
Body Control Module Bracket Replacement
Power Mode Master
This vehicles body control module (BCM) functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.
Serial Data Gateway
The body control module (BCM) in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
One example of this necessary communication is the communication between the engine control module (ECM)/powertrain control module (PCM) which is high speed serial data and Theft Deterrent Module which is low speed serial data. If these modules can not exchange information, the vehicle will not start.
Communication between the BCM and a scan tool can be on the high speed GMLAN network or low speed GMLAN network. If one network is lost, the BCM can still communicate with the scan tool. A lost communication DTC typically is set in modules other than the module with a communication failure.
Body Control Module
The various body control module (BCM) input and output circuits are described in the corresponding functional areas indicated on the BCM electrical schematics. Some BCM functions with the subsystems may be as a gateway only or as an enable for the system. The BCM related systems/subsystems include, but are not limited to the following
- Antilock Brake System (ABS)-Refer to «ABS Description and Operation (Under 8600 GVW)»(ref-278027-S34186788952008012100000) or «ABS Description and Operation (Equal to or Over 8600 GVW)»(ref-278027-S12138837042008012100000) .
- Automatic Day-Night Mirror-Refer to «Automatic Day-Night Mirror Description and Operation»(ref-278022-S33115687882008012100000) .
- Cruise Control System-Refer to «Cruise Control Description and Operation»(ref-278059-S42389829672008012100000) .
- Electrical Power Management (EPM)-Refer to «Electrical Power Management Description and Operation»(ref-278006-S35041610322008012100000) .
- Exterior Lighting-Refer to «Exterior Lighting Systems Description and Operation»(ref-277990-S37916934242008012100000) .
- Horn System-Refer to «Horns System Description and Operation»(ref-278023-S18697276912008012100000) .
- HVAC-Refer to «Air Delivery Description and Operation»(ref-277997-S21943014992008012100000) and «Air Temperature Description and Operation»(ref-277997-S19219715292008012100000) .
- Instrument Cluster Indicator Control-Refer to «Instrument Cluster Description and Operation»(ref-277996-S41966883042008012100000) .
- Interior Lighting-Refer to «Interior Lighting Systems Description and Operation»(ref-277990-S41670391962008012100000) .
- Power Door Lock System-Refer to «Power Door Locks Description and Operation»(ref-278003-S03700349662008012100000) .
- Rear Window Defogger System-Refer to «Rear Window Defogger Description and Operation»(ref-278004-S12336574192008012100000) .
- Redundant Steering Wheel Controls-Refer to «Steering Wheel Controls Description and Operation»(ref-278061-S40514799772008012100000) .
- Remote Function Actuation (RFA) Control-Refer to «Keyless Entry System Description and Operation»(ref-278024-S30485436172008012100000) .
- Retained Accessory Power (RAP)-Refer to «Retained Accessory Power (RAP) Description and Operation»(ref-278007-S22461613372008012100000) .
- Shift Lock Control System-Refer to «Automatic Transmission Shift Lock Control Description and Operation»(ref-278062-S17450862112008012100000) .
- Starting System-Refer to «Starting System Description and Operation»(ref-278006-S10575521652008012100000) .
- Supplemental Inflatable Restraint (SIR) System-Refer to «SIR System Description and Operation»(ref-277986-S02875551452008012100000) .
- Theft Deterrent-Refer to «Content Theft Deterrent (CTD) Description and Operation»(ref-278046-S34601093462008012100000) .
- Tire Pressure Monitor (TPM) System-Refer to «Tire Pressure Monitor Description and Operation»(ref-278032-S21483277452008012100000) .
- Wiper/Washer System Functions-Refer to «Wiper/Washer System Description and Operation»(ref-278010-S38606246202008012100000) .
Export Body Control Module
The export body control system has an additional body control module located in the rear of the vehicle. This additional body control module is referred to as the XBCM. The XBCM has discrete input and output terminals to control additional vehicle body functions not supported by the primary body control module (BCM). The XBCM is wired to the GMLAN low speed serial data buss and the BCM and acts as a gateway between them. If the XBCM does not communicate, various rear end lighting such as rear fog lamps and trailer lighting will be impaired.
The various input and output circuits are described in the corresponding functional areas indicated on the XBCM electrical schematics. Some XBCM functions with the subsystems may be as a gateway only or as an enable for the system. The XBCM related systems/subsystems include, but are not limited to the following
- Exterior lighting-Refer to «Exterior Lighting Systems Description and Operation»(ref-277990-S37916934242008012100000) .
- Instrument cluster indicator control-Refer to «Instrument Cluster Description and Operation»(ref-277996-S41966883042008012100000) .
- Theft deterrent-Refer to «Content Theft Deterrent (CTD) Description and Operation»(ref-278046-S34601093462008012100000) .
Data Link Connector (DLC)
The data link connector (DLC) is a standardized 16-cavity connector. The DLC low speed serial data circuit is connected directly to the instrument panel (I/P) splice then to all other splices or modules. Connector design and location is dictated by an industry wide standard, and is required to provide the following
- Pin 1 GMLAN low speed communications terminal
- Pin 4 scan tool power ground terminal
- Pin 5 common signal ground terminal
- Pin 6 high speed GMLAN serial data bus (+) terminal
- Pin 14 high speed GMLAN serial data bus (-) terminal
- Pin 16 scan tool power, battery positive voltage terminal
Serial Data Reference
The scan tool communicates over the various busses on the vehicle. When a scan tool is installed on a vehicle, the scan tool will try to communicate with every module that could be optioned into the vehicle. If an option is not installed on the vehicle, the scan tool will display No COMM for that options specific control module.
In order to avert misdiagnoses of No Communication with a specific module, refer to Data Link References for a list of modules, the busses they communicate with, and the RPO codes for a specific module.