Contents Wiring diagrams Section: Communication Devices All sections

Computer/integrating Systems: Other Saturn ION I

Communication Devices ~2261 words

Conditions for Setting the DTCs

  1. No valid messages are detected on the class 2 serial data circuit.
  2. The voltage level detected on the class 2 serial data circuit is in one of the following conditions: High Low
  3. The above conditions are met for approximately 3 seconds.

Action Taken When the DTCs Sets

  1. The module suspends all message transmission.
  2. The module uses default values for all parameters received on the serial data circuits.
  3. The module inhibits the setting of all other communication DTCs.
  1. The module suspends all message transmission.
  2. The module uses default values for all parameters received on the serial data circuits.
  3. The module inhibits the setting of all other communication DTCs.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Retained Accessory Power (RAP) On After Timeout

StepActionYesNo
Schematic Reference: Retained Accessory Power (RAP) Schematics
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Install a scan tool. With the scan tool, observe all door jamb switches. Open and close each door. Does the scan tool display change from active to inactive?Go to Step 3Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
3Close all of the doors. Turn the ignition switch to the ON position, then to the OFF position. Wait 10 minutes. Attempt to operate the radio and/or the power windows after 10 minutes has elapsed. Do any of the items operate after 10 minutes has elapsed?Go to Step 4Go to Step 10
4Remove the accessory (ACC) relay from the body control module (BCM). Test the ACC relays + control terminal on the BCM for battery voltage, after the 10 minute timer has elapsed. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Does battery voltage exist after 10 minutes has expired?Go to Step 8Go to Step 5
5With the ACC relay removed from the BCM, does the radio or power windows operate?Go to Step 6Go to Step 7
6Repair the short to voltage in the battery positive voltage relay output circuit, which feeds the radio and power windows. Refer to Wiring Repairs and Circuit Testing in Wiring Systems. Is the repair complete?Go to Step 10
7Replace the ACC relay on the BCM. Is the repair complete?Go to Step 10
8Inspect the BCM for poor connections and intermittent faults. Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Connector Repairs Inducing Intermittent Fault Conditions Testing for Electrical Intermittents Did you find and correct the condition?Go to Step 10Go to Step 9
9Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 10
10Operate the system in order to verify the repair. Does retained accessory power (RAP) power mode function normally?System OKGo to Step 2

Retained Accessory Power (RAP) On After Timeout

Retained Accessory Power (RAP) Inoperative

StepActionYesNo
Schematic Reference: Retained Accessory Power (RAP) Schematics
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Test the following circuits of the body control module (BCM) for an open or a short to ground: The battery input voltage The ignition input voltage The ignition output voltage Refer to the following: Body Control System Schematics Circuit Testing in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct condition?System OKGo to Step 3
3Connect a scan tool. With the scan tool, observe all door jamb switches. Open and close each door. Does the scan tool display change from active to inactive?Go to Step 4Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
4With all doors closed, turn the ignition ON with the engine OFF. Turn the ignition OFF. Operate the radio and power windows during the 10 minute retained accessory power (RAP) time period. Do any of the items operate after 10 minutes has elapsed?Go to Step 11Go to Step 5
5Test for a battery voltage supply, before the accessory (ACC) relay contacts. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is battery voltage present?Go to Step 7Go to Step 6
6Locate and repair the supply voltage malfunction to the ACC relay. Refer to Testing for a Short to Voltage in Wiring Systems. Was there a inactive supply circuit to the BCM and did you repair it?Go to Step 11Go to Step 9
7With RAP power mode enabled, test for a battery voltage supply output, after the ACC relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you locate and repair the fault?Go to Step 11Go to Step 8
8Replace the ACC relay. Is the replacement complete?Go to Step 11
9Inspect for poor connections or terminal damage at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 10
10Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 11
11Enable RAP power mode to verify the repair. Did you correct the condition?System OKGo to Step 2

Retained Accessory Power (RAP) Inoperative

Control Module References

Control ModuleSchematicRepair InstructionProgramming and Setup
Diagnostic System Check - Vehicle in Vehicle DTC Information Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information Symptoms - Vehicle in Vehicle DTC Information
Audio AmplifierRadio/Audio System Schematics in EntertainmentAmplifier Replacement in EntertainmentThis device requires no programming or setup.
Body Control ModuleBody Control System SchematicsBody Control Module ReplacementBody Control Module Programming and Setup
Communication Interface Module (OnStar ®)OnStar Schematics in Cellular CommunicationCommunication Interface Module Replacement in Cellular CommunicationOnStar Reconfiguration (Gen 6) or OnStar Reconfiguration (Gen 6.1) in Cellular Communication after communication interface module replacement
Digital Radio Receiver (DRR)Radio/Audio System Schematics in EntertainmentReceiver Replacement - Digital Radio in EntertainmentDigital Radio Receiver Setup in Entertainment after DRR replacement
Electronic Brake Control Module (Antilock Brake System)ABS Schematics in Antilock Brake SystemElectronic Brake Control Module Replacement in Antilock Brake SystemThis device requires no programming or setup.
Engine Control ModuleEngine Controls Schematics in Engine Controls - 2.2L (L61)Engine Control Module (ECM) Replacement in Engine Controls - 2.2L (L61)Engine Control Module Programming and Setup
Ignition Control ModuleEngine Controls Schematics in Engine Controls - 2.2L (L61)Ignition Control Module Replacement in Engine Controls - 2.2L (L61)This device requires no programming or setup.
Inflatable Restraint Sensing and Diagnostic Module (Supplemental Inflatable Restraint)SIR Schematics in SIRInflatable Restraint Sensing and Diagnostic Module Replacement in SIRInflatable Restraint Sensing and Diagnostic Module Programming and Setup
Instrument Panel ClusterInstrument Cluster Schematics in Instrument Panel, Gages, and ConsoleInstrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and ConsoleThis device requires no programming or setup.
Power Steering Control Module (Electric Power Steering)Power Steering System Schematics in Power Steering SystemSteering Column Replacement in Steering Wheel and ColumnPower Steering Control Module Programming and Setup
Powertrain Control ModuleEngine Controls Schematics in Engine Controls - 2.0LPowertrain Control Module (PCM) Replacement in Engine Controls - 2.0LPowertrain Control Module Programming and Setup
RadioRadio/Audio System Schematics in EntertainmentRadio Replacement in EntertainmentRadio Setup in Entertainment after radio replacement
Transmission Control ModuleAutomatic Transmission Controls Schematics in Automatic Transaxle - 4T40-E/4T45-ETransmission Control Module Programming and Setup

Control Module 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 ModuleData Link TypeDiagnostic Procedure
Schematic Reference: Data Link Connector (DLC) Schematics
Body Control Module (BCM)High Speed GMLAN Class 2Scan Tool Does Not Communicate with High Speed GMLAN Device Scan Tool Does Not Communicate with Class 2 Device
Electronic Brake Control Module (EBCM)High Speed GMLAN Class 2Scan Tool Does Not Communicate with High Speed GMLAN Device Scan Tool Does Not Communicate with Class 2 Device
Engine Control Module (ECM)High Speed GMLAN Class 2Scan Tool Does Not Communicate with High Speed GMLAN Device Scan Tool Does Not Communicate with Class 2 Device
Inflatable Restraint Sensing and Diagnostic Module (SDM)Class 2Scan Tool Does Not Communicate with Class 2 Device
Instrument Panel Cluster (IPC)Class 2Scan Tool Does Not Communicate with Class 2 Device
Power Steering Control Module (PSCM)Class 2Scan Tool Does Not Communicate with Class 2 Device
RadioLow Speed GMLANScan Tool Does Not Communicate with Low Speed GMLAN Device
Transmission Control Module (TCM)High Speed GMLANScan Tool Does Not Communicate with High Speed GMLAN Device
Vehicle Communication Interface Module (VCIM)Class 2Scan Tool Does Not Communicate with Class 2 Device

Data Link References

Body Control Module (BCM) Programming/RPO Configuration

  1. The body control module (BCM) must be programmed with the proper RPO configurations. The BCM stores the information regarding the vehicle options and if the BCM is not properly configured with the correct RPO codes, the BCM will not control all of the features properly. Ensure that the following conditions exist in order to prepare for BCM programming: The battery is fully charged. The ignition switch is in the ON position. The data link connector (DLC) is accessible. All disconnected modules and devices are reconnected before programming.
  2. To setup a new BCM, use the Tech 2 in conjunction with the Saturn Service Stall System. Refer to «Service Programming System (SPS)»(ref-196948-S25874455652005101000000) in Programming and Setup.
  3. If the BCM fails to accept the program, perform the following steps: Inspect all BCM connections. Verify that the scan tool has the latest software version.

Passlock Learn Procedures

IMPORTANTIf any module or device listed is replaced, programming of the module must be done prior to performing the Passlock Learn procedure.

Perform the Learn Procedure if any of the following components have been replaced

  1. The body control module (BCM)
  2. The ignition switch
  3. The engine control module (ECM)

Refer to Programming Theft Deterrent System Components in Theft Deterrent for the proper procedure.

IMPORTANTAfter programming, perform the following to avoid future misdiagnosis
  1. Turn the ignition OFF for 10 seconds.
  2. Connect the scan tool to the data link connector.
  3. Turn the ignition ON with the engine OFF.
  4. Use the scan tool in order to retrieve history DTCs from all modules.
  5. Clear all history DTCs.

The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following

  1. Scan tool power battery positive voltage at terminal 16
  2. Scan tool power ground at terminal 4
  3. Common signal ground at terminal 5
  4. Class 2 signal at terminal 2
  5. GMLAN high circuit at terminal 6
  6. GMLAN low circuit at terminal 14

GMLAN Serial Data Line

The GMLAN serial data communications circuit used on this vehicle is in a linear topology. The following modules are connected to the link, in order from DLC to the end of the linear configuration

The following modules communicate on the GMLAN serial data circuit

  1. The engine control module (ECM)
  2. The radio
  3. The transmission control module (TCM)

Class 2 Serial Data Line

The class 2 serial data communications circuit on this vehicle is in a ring star configuration.

The following modules communicate on the class 2 serial data circuit

  1. The body control module (BCM)
  2. The electronic brake control module (EBCM)
  3. The electric power steering (EPS)
  4. The instrument panel cluster (IPC)
  5. The inflatable restraint sensing and diagnostic module (SDM)
  6. The vehicle communication interface module (VCIM)

Power Mode Master

This vehicles BCM functions as the Power Mode Master (PMM). Refer to Power Mode Description and Operation for a complete description of the power mode functions.

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. The BCM functions include the following

  1. A/C compressor request-Refer to «Air Temperature Description and Operation»(ref-196990-S13132004112005101000000) in HVAC Systems - Manual.
  2. A/C cooling fan-Refer to «Air Delivery Description and Operation»(ref-196990-S08986362412005101000000) in HVAC Systems - Manual.
  3. Battery rundown protection (inadvertent power) - Refer to «Interior Lighting Systems Description and Operation»(ref-196945-S19153949522005101000000) in Lighting Systems.
  4. Brake fluid level sensing-Refer to «Brake Warning System Description and Operation»(ref-196979-S15535191102005101000000) in Hydraulic Brakes.
  5. Bulb check-Refer to «Instrument Panel Cluster (IPC) Description and Operation»(ref-196967-S01185220972005101000000) in Instrument Panel, Gages, and Console.
  6. Chimes-Refer to «Audible Warnings Description and Operation»(ref-196967-S26666832892005101000000) in Instrument Panel, Gages, and Console. Check gages Door ajar warning Headlamps ON Key-in-ignition Oil reset Park brake warning Seat belt not fastened Turn signal ON
  7. Door lock interface-Refer to «Power Door Locks Description and Operation»(ref-196946-S28587569892005101000000) in Doors.
  8. Electronic steering control (ESC)-Refer to «Power Steering System Description and Operation»(ref-196975-S05408842342005101000000) in Power Steering System.
  9. Engine coolant level sensing-Refer to «Cooling System Description and Operation»(ref-196980-S12078392632005101000000) in Engine Cooling.
  10. Exterior and interior lighting control-Refer to «Exterior Lighting Systems Description and Operation»(ref-196945-S08180006272005101000000) in Lighting Systems. Automatic lighting control Daytime running lights (DRL) Fog lamps Park brake lights Turn hazard lamps
  11. Gage control-Refer to «Instrument Panel Cluster (IPC) Description and Operation»(ref-196967-S01185220972005101000000) in Instrument Panel, Gages, and Console.
  12. Horn interface-Refer to «Horns System Description and Operation»(ref-196944-S20197825302005101000000) in Horns.
  13. Instrument cluster indicator control-Refer to «Instrument Panel Cluster (IPC) Description and Operation»(ref-196967-S01185220972005101000000) in Instrument Panel, Gages, and Console.
  14. Interior lighting-Refer to «Interior Lighting Systems Description and Operation»(ref-196945-S19153949522005101000000) in Lighting Systems.
  15. Key-in-ignition sensing-Refer to «Audible Warnings Description and Operation»(ref-196967-S26666832892005101000000) in Instrument Panel, Gages, and Console.
  16. Parking brake state sensing-Refer to «Brake Warning System Description and Operation»(ref-196979-S15535191102005101000000) in Hydraulic Brakes.
  17. Retained accessory power (RAP)-Refer to «Retained Accessory Power (RAP) Description and Operation»(ref-196943-S42419798172005101000000) .
  18. Rear compartment interface-Refer to «Power Door Locks Description and Operation»(ref-196946-S28587569892005101000000) in Doors.
  19. Rear defogger-Refer to «Rear Window Defogger Description and Operation»(ref-196942-S18937187062005101000000) in Stationary Windows.
  20. Remote function control-Refer to «Keyless Entry System Description and Operation»(ref-196959-S22174068142005101000000) in Keyless Entry.
  21. Seat belt use sensing-Refer to «Seat Belt System Description and Operation»(ref-196983-S23999570092005101000000) in Seat Belts.
  22. Theft deterrent-Refer to «Theft Systems Description and Operation»(ref-196961-S12223538302005101000000) in Theft Deterrent.
  23. Washer solvent level sensing-Refer to «Wiper/Washer System Description and Operation»(ref-196964-S36332362712005101000000) in Wipers/Washer Systems.
  24. Wiper/washer-Refer to «Wiper/Washer System Description and Operation»(ref-196964-S36332362712005101000000) in Wipers/Washer Systems.

Serial Data Power Mode Master

On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle the PMM is the body control module (BCM). The PMM receives 3 discrete ignition switch signals to differentiate which power mode will be sent over the Serial Data circuits. The table below illustrates the state of these inputs in correspondence to the ignition switch position

Ignition Switch PositionAccessoryRun/CrankOff/Run/CrankPower Mode Transmitted
IMPORTANT: States marked with the * indicate the positive Passlock™ voltage level not vehicle positive battery voltage.
Off000 Key out 1 Key inOFF/Awake or RAP
Start011*Crank
Accessory100Accessory
Run111Run
IMPORTANT
States marked with the * indicate the positive Passlock™ voltage level not vehicle positive battery voltage.

3-Wire Ignition Switch Table

Relay Controlled Power Mode

The body control module (BCM) uses the discrete ignition switch inputs Off/Run/Crank, Accessory and Run/Crank to distinguish the correct power mode. These circuits are also routed to the Run/Crank and Accessory relays for relay controlled power feeds during the appropriate power mode.

Run/Crank Relay

The relay uses a hot at all times B+ power source derived from the underhood electrical center. The Run/Crank relay supplies a power signal to the following circuits when the a Run or Crank power mode is selected

  1. Backup lamp circuit
  2. Electronic brake control module (EBCM)
  3. Engine control module (ECM)
  4. Ignition control module (ICM)
  5. Park neutral position switch
  6. Transmission circuit 1 and 2

Accessory (ACC) Relay

The accessory (ACC) relay is energized when the Run or Accessory power mode has been selected. The relay uses a Hot At All Times B+ power source derived from the underhood electrical center. The ACC relay is also energized by the BCM to supply power during the retained accessory power (RAP) power mode. The following devices are controlled by this relay

  1. Auxiliary power outlets
  2. EC mirrors
  3. Ignition lock solenoid
  4. Power windows
  5. Power mirrors
  6. Radio
  7. Rear compartment lid release
  8. Sunroof
  9. Wiper washers

Fail-Safe Operation

Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the power mode master (PMM) fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.

Serial Data Messages

The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to RUN. In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

Discrete Ignition Signals

Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, battery positive voltage, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 volts, the modules will fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

BCM Wake-Up/Sleep States

The body control module (BCM) is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the BCM to wake-up when activated or deactivated. Multiple switch inputs are needed in order to sense both the insertion of the ignition key and the power mode requested. This would allow the BCM to enter a sleep state when the key is IN or OUT of the ignition.

The BCM will enter a wake-up state if any of the following wake-up inputs are detected

  1. Activity on the serial data line
  2. Detection of a battery disconnect and reconnect condition
  3. Headlamps are ON.
  4. Ignition is turned ON.
  5. Key-in-ignition switch
  6. Park lamps are ON.

The BCM will enter a sleep state when all of the following conditions exist

  1. The ignition switch is OFF.
  2. No activity exists on the serial data line.
  3. No outputs are commanded.
  4. No delay timers are actively counting.
  5. No wake-up inputs are present.

If all these conditions are met the BCM will enter a low power or sleep condition. This condition indicates that the BCM, which is the PMM of the vehicle, has sent an OFF-ASLEEP message to the other systems on the serial data line.

Retained Accessory Power (RAP) Power Mode

Retained accessory power (RAP) is a power mode that permits the operation of selected customer convenience items for approximately 10 minutes after the ignition switch is turned OFF. RAP power mode is enabled by the body control module (BCM) and controls certain BCM features.

The BCM monitors the ignition switch position, battery voltage and passenger compartment door status to determine whether RAP power mode should enable. If the ignition switch transitions from ON to OFF, the battery voltage is within the acceptable range, and the passenger compartment doors are closed, the BCM enables RAP power mode. After the 10 minutes have elapsed, the BCM will cease to produce the RAP power mode.

Some BCM features, such as the interior courtesy lamps, will function after the 10 minute RAP time limit has elapsed. This is normal and does not mean RAP power mode is malfunctioning. The BCM enables the following functions in RAP power mode

  1. The radio
  2. The sunroof, internal to BCM-if equipped
  3. The power windows, internal to BCM-if equipped

RAP is disabled when

  1. A door is opened.
  2. The BCM detects low battery voltage.
  3. The transition of ignition switch from OFF to ON or ACC.
  4. 10 minutes have elapsed after the ignition was turned OFF.
IMPORTANTThere may be some functions of the vehicle that are hard-wired straight to the battery; these are the exceptions.

ACC Relay

The accessory (ACC) relay switches the accessory power to the vehicle and also severs as the retained accessory power (RAP) relay when the body control module (BCM) commands a RAP power mode. The ACC relay is installed directly on the BCM and its supply current is derived from the fuse block underhood junction box. The BCM on this vehicle is integrated with a bussed electrical center (BEC), because the BCM and the BEC are integrated. Replacement of the BCM may be the only way to repair certain RAP malfunctions, e.g., internal short to B+ or ground.