Computer/integrating Systems: Overview Pontiac G6 I

Computer/Integrating Systems Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs. IMPORTANT: Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires. The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)

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Callouts For (Scheme 10)

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Callouts For (Scheme 11)

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Computer/Integrating Systems Connector End Views

Data Link Connector (DLC)

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Computer/Integrating Systems Connector End Views

Body Control Module (BCM) C1

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Computer/Integrating Systems Connector End Views

Body Control Module (BCM) C2

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Computer/Integrating Systems Connector End Views

Body Control Module (BCM) C3

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Computer/Integrating Systems Connector End Views

Body Control Module (BCM) C4

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This tests the ignition switch for a short circuit between the 12-volt reference supply circuit and the ignition 1 circuit in the OFF position.
2. 4: This tests the wiring of the ignition 1 circuit for a short to ground or voltage.
3. 5: This tests the ignition switch for a closed circuit between the ignition switch 12-volt reference supply circuit and the ignition 1 circuit in the Run and Crank switch positions. Care must be taken as the engine may crank during this test.

DTC B1370

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This tests the ignition switch for a short circuit between the 12-volt reference supply circuit and the ACCESSORY circuit in the OFF position.
2. 4: This tests the wiring of the ACCESSORY circuit for a short to ground or voltage.
3. 5: This tests the ignition switch for a closed circuit between the ignition switch 12-volt reference supply circuit and the ACCESSORY circuit in the Run and Accessory switch positions. Care must be taken as the engine may crank during this test.

DTC B1380

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This tests the OFF/RUN/CRANK circuit for a short circuit to B+ and ground. Because of the control over powermoding, this step must be performed with the switch in the OFF position. Any shorts to ground during this step could be a short to a voltage circuit that is only powered in Run or Accessory. The loads on these circuits would indicate a short to ground, but the cause would have to be traced thorough the OFF/RUN/CRANK circuit and repaired.
2. 4: This tests the ignition switch contacts of the OFF/RUN/CRANK circuit for merit.
3. 5: This tests the OFF/RUN/CRANK, +5-volt and +12-volt circuits for an open.

DTC B1441

The numbers below refer to the step numbers on the diagnostic table

1. 3: If body control module (BCM) will not power up the vehicle cannot establish the correct power mode. This step tests for the correct power supply conditions for the BCM.
2. 4: If DTC U2105 to U2199 or DTC U0100 to U0199 is set as history and you can communicate with the suspect module, the malfunction is an intermittent communication buss, power supply, ground or internal module connection.
3. 5: This step tests for the correct power supply conditions of the suspect module or modules.
4. 7: The powertrain control module (PCM) that is used in the 3.5L (LX9) powertrain package can lose communication with the buss if there is a malfunction in the camshaft position (CMP) or the crankshaft position (CKP) sensors 12-volt reference circuit.
5. 8: This step identifies which of the GMLAN busses the module or modules use for communication. Use the Data Link References for identifying the correct buss to analyze.
6. 13: The module which was not communicating due to an open in the GMLAN serial data circuits may have set Loss of Communication DTCs for those modules that it was monitoring.
7. 14: The modules which can communicate indicate the module which cannot communicate. You must clear the DTC from these modules to avoid future misdiagnosis. DTC U0100-U0299 Step Action Yes No Schematic Reference: «Data Link Connector (DLC) Schematics»(ref-242975-S35803175642006082100000) Connector End View Reference: «Master Electrical Component List»(/pontiac/g6/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views__master-electrical-component-list) in Wiring Systems 1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2 Go to «Diagnostic System Check - Vehicle»(ref-242980-S19231637582006082100000) in Vehicle DTC Information 2 Install a scan tool. Turn ON the ignition, with the engine OFF. Attempt to communicate with body control module (BCM). Were you able to communicate with BCM? Go to Step 4 Go to Step 3 3 Turn the ignition OFF. Disconnect the harness connectors from the BCM. Test the following circuits of the BCM harness connector for the indicated condition. Refer to «Circuit Testing»(ref-242973-S03159704652006082100000) and «Wiring Repairs»(ref-242973-S18890039002006082100000) in Wiring Systems. Switched and constant B+ supply circuits, for power Ground circuits, for continuity All communications circuits, for continuity Did you find and correct the condition? Go to Step 11 Go to Step 9 4 Attempt to communicate with all of the modules on the vehicle. Were you able to communicate with all of the modules? Go to «Testing for Intermittent Conditions and Poor Connections»(ref-242973-S38322986792006082100000) in Wiring Systems Go to Step 5 5 Test the following circuits of the modules that do not communicate: Switched B+ supply circuits Constant B+ supply circuits Ground circuits Did you find and correct the condition? Go to Step 9 Go to Step 6 6 Is the non-communicating module the powertrain control module (PCM) on a vehicle equipped with the 3.5L (LX9) VIN 8 engine? Go to Step 7 Go to Step 8 7 Test the 12-volt reference circuit of the camshaft position sensor and the crankshaft position sensor of the 3.5L LX9 PCM for a short to ground or low reference. Refer to «Engine Controls Schematics»(ref-242989-S17436945462006082100000) in Engine Controls - 3.5L (LX9) for the correct circuit identification. Did you find and correct the condition? Go to Step 11 Go to Step 8 8 Refer to «Data Link References»(ref-242975-S04408354942006082100000) to identify the GMLAN buss or busses that the modules use to communicate and make a note. If more than one module is not communicating, use the data link connector (DLC) schematic to determine which module is closest to the DLC. Start the analysis at that module. Refer to «Data Link Connector (DLC) Schematics»(ref-242975-S35803175642006082100000). Disconnect the harness connectors from the non-communicating modules. Test for an open circuit in the appropriate buss between the GMLAN terminals of the disconnected harness connector and the DLC. Use the note from item 1 for buss identification. Did you find and correct the condition? Go to Step 11 Go to Step 9 9 Inspect for poor connections at the harness connector of the non-communicating module. Refer to «Testing for Intermittent Conditions and Poor Connections»(ref-242973-S38322986792006082100000) and «Connector Repairs»(ref-242973-S32323876832006082100000) in Wiring Systems. Did you find and correct the condition? Go to Step 11 Go to Step 10 10 IMPORTANT: Perform the module setup procedure, if required. Replace the non-communicating module. Refer to «Control Module References»(ref-242975-S40456744722006082100000) Did you complete the replacement? Go to Step 11 - 11 Make sure that the scan tool has been cycled OFF for at least 15 seconds in order to reset it. Install the scan tool, if necessary. Turn ON the ignition, with the engine OFF. Retrieve DTCs from the module that was not communicating. Does the scan tool display any DTCs which do not begin with a "U"? Go to the «Diagnostic System Check - Vehicle»(ref-242980-S19231637582006082100000) in Vehicle DTC Information Go to Step 12 12 Use the scan tool in order to clear the DTCs. Did you complete the action? Go to Step 13 - 13 Retrieve DTCs from the modules which had the Loss of Communications DTC set. Does the scan tool display any DTCs which do not begin with a "U"? Go to the «Diagnostic System Check - Vehicle»(ref-242980-S19231637582006082100000) in Vehicle DTC Information Go to Step 14 14 Attempt to communicate with all the modules on the vehicle. Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared. Does U2105-U2199 or U0100-U0299 set in any module? Go to Step 2 System OK

The numbers below refer to the step numbers on the diagnostic table

1. 3: If body control module (BCM) will not power up the vehicle cannot establish the correct power mode. This step tests for the correct power supply conditions for the BCM.
2. 4: If DTC U2103 is set as history and you can communicate with the suspect module, the malfunction is an intermittent communication buss, power supply, ground or internal module connection.
3. 5: This step tests for the correct power supply conditions of the suspect module or modules.
4. 6: This step identifies which of the GMLAN busses the module or modules use for communication. Use the «Data Link References»(ref-242975-S04408354942006082100000) for identifying the correct buss to analyze.
5. 11: The module which was not communicating due to an open in the GMLAN serial data circuits may have set Loss of Communication DTCs for those modules that it was monitoring.
6. 20: The modules which can communicate indicate the module which cannot communicate. You must clear the DTC from these modules to avoid future misdiagnosis.

DTC U2103

The numbers below refer to the step numbers on the diagnostic table

1. 3: If the body control module (BCM) will not power up the vehicle cannot establish the correct power mode. This step tests for the correct power supply conditions for the BCM.
2. 4: If DTC U2105 to U2177 are set as history and you can communicate with the suspect module, the malfunction is an intermittent communication buss, power supply, ground or internal module connection.
3. 5: This step tests for the correct power supply conditions of the suspect module or modules.
4. 7: The powertrain control module (PCM) that is used in the 3.5L (LX9) powertrain package can lose communication with the buss if there is a malfunction in the camshaft position (CMP) or the crankshaft position (CKP) sensors 12-volt reference circuit.
5. 8: This step identifies which of the GMLAN busses the module or modules use for communication. Use the «Data Link References»(ref-242975-S04408354942006082100000) for identifying the correct buss to analyze.
6. 13: The module which was not communicating due to an open in the GMLAN serial data circuits may have set Loss of Communication DTCs for those modules that it was monitoring.
7. 14: The modules which can communicate indicate the module which cannot communicate. You must clear the DTC from these modules to avoid future misdiagnosis.

DTC U2105-U2199

1. Perform the «Diagnostic System Check - Vehicle»(ref-242980-S19231637582006082100000) in Vehicle DTC Information 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.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to: «Data Link Communications Description and Operation»(ref-242975-S21426007452006082100000) «Body Control System Description and Operation»(ref-242975-S28195815612006082100000) «Retained Accessory Power (RAP) Description and Operation»(ref-242975-S09868106482006082100000)

The number below refers to the step number on the diagnostic table.

1. 4: If the battery positive voltage and ground circuits of the DLC are functioning properly. The malfunction must be due to the scan tool.

Scan Tool Does Not Power Up

The numbers below refer to the step numbers on the diagnostic table.

1. 2: A partial malfunction in the high speed GMLAN serial data circuits uses a different procedure from a total malfunction of the high speed GMLAN data circuits. Refer to «Data Link References»(ref-242975-S04408354942006082100000) to identify which modules communicate on the high speed GMLAN serial data circuits.
2. 3: The DTC U2100 may be retrieved with a history status, but is not the cause of the present condition.
3. 8: Data link connector terminals 6 and 14 provide the connection to the GMLAN serial data high circuit and the GMLAN serial data low circuit respectively.
4. 17: The communication malfunction may have prevented diagnosis of the customer complaint.

Scan Tool Does Not Communicate with High Speed GMLAN Device

The numbers below refer to the step numbers on the diagnostic table.

1. 2: A partial malfunction in the low speed GMLAN serial data circuits uses a different procedure from a total malfunction of the low speed GMLAN data circuits. Refer to «Data Link References»(ref-242975-S04408354942006082100000) to identify which modules communicate on the low speed GMLAN serial data circuits.
2. 3: The DTC U2100 may be retrieved with a history status, but is not the cause of the present condition.
3. 7: Data link connector terminal 1 provides the connection to the GMLAN serial data low circuit and the GMLAN serial data low circuit respectively.
4. 16: The communication malfunction may have prevented diagnosis of the customer complaint.

Scan Tool Does Not Communicate with Low Speed GMLAN Device

The numbers below refer to the step numbers on the diagnostic table.

1. 6: This step tests for battery voltage on the incorrect signal circuits.
2. 7: This step tests for no battery voltage on the required signal circuits.
3. 8: If any ignition switch parameters that should be inactive in the present ignition switch position are active, 2 ignition switch signal circuits may be shorted together.
4. 9: This step eliminates open circuits as the cause of the malfunction.

Power Mode Mismatch

Body Control System Description and Operation

This vehicle's body control module (BCM) has a bussed electrical center integrated into the housing. Body control relays and fuses are installed directly on the BCM, which simplifies wiring and junction blocks on the vehicle. The body control system consists of the BCM and its associated controls. Battery positive voltage is provided to the BCM from IBCM BATT 1 fuse and the IBCM BATT 2 fuse in the underhood fuse block. The module grounds are wired to ground G201, G203 and G305. The BCM is wired to the GMLAN High speed serial data buss, and the GMLAN Low speed serial data buss, as well as discrete input and output terminals to control the functions of the vehicle's body.

Power Mode Description and Operation

Power to many of this vehicle's circuits are controlled by the module that is designated the power mode master (PMM). This vehicle's PMM is the body control module (BCM). The PMM controls which power mode (Run, Accessory, Crank, Retained Accessory Power, or Off) is active.

See also:
• Master Electrical Component List