Data Communication Schematic Icons
Data Communication 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 . 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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Scheme 9
| Callout | Component Name |
|---|---|
| 1 | Data Link Connector (DLC) |
| 2 | Body Control Module (BCM) |
| 3 | Fuse Block-I/P |
Scheme 10
| Connector Part Information OEM: 12084945 Service: See Catalog Description: 16-Way F Micro-Pack 100 Series (GY) |
Body Control Module (BCM) C1 Connector Parts Information
| Pin | Wire Color | Circuit No. | Function |
|---|---|---|---|
| A1 | Not Used | ||
| A2 | L-GN | 1391 | Driver Door Unlock Relay Control (AU0) |
| A3 | L-BU | 195 | Door Lock Relay Control (AU0) |
| A4 | WH | 194 | Door Unlock Relay Control (AU0) |
| A5-A6 | Not Used | ||
| A7 | OG/BK | 781 | Driver Door Lock Switch Unlock Signal |
| A8 | RD/BK | 780 | Driver Door Lock Switch Lock Signal |
| B1 | Not Used | ||
| B2 | D-BU | 1201 | Headlamp Low Beam Signal |
| B3 | Not Used | ||
| B4 | GY | 731 | EVAP Temperature Sensor Signal (Except HP7) |
| B5 | Not Used | ||
| B6 | L-GN/BK | 1137 | DRL Ambient Light Sensor Signal (T82) |
| B7 | YE/BK | 1138 | DRL Ambient Light Sensor Low Reference (T82) |
| B8 | L-GN | 66 | A/C Request Signal (Except HP7) |
Body Control Module (BCM) C1 Connector Terminal Identification
Scheme 11
| Connector Part Information OEM: 12110088 Service: See Catalog Description: 24-Way F Micro-Pack 100 Series (GY) |
Body Control Module (BCM) C2 Connector Parts Information
| Pin | Wire Color | Circuit No. | Function |
|---|---|---|---|
| A1 | Not Used | ||
| A2 | L-BU | 1134 | Park Brake Switch Signal |
| A3 | PK | 1200 | Headlamp High Beam Signal |
| A4 | BN | 41 | Run Ignition 3 Voltage |
| A5 | PU | 333 | Brake Fluid Level Switch Signal |
| A6 | BN | 96 | Windshield Wiper Switch Pulse Delay Signal |
| A7 | L-BU | 1788 | Traction Control Switch Signal (1) |
| A8 | PK | 94 | Windshield Washer Switch Signal |
| A9 | RD | 228 | Windshield Washer Pump Control |
| A10 | PK | 339 | Ignition 1 Voltage |
| A11 | L-GN | 80 | Key In Ignition Switch Signal |
| A12 | BK/WH | 746 | Passenger Doors Ajar Switch Signal |
| B1 | YE | 749 | Security Indicator Control |
| B2 | GY/BK | 745 | Left Front Door Ajar Switch Signal |
| B3 | L-BU | 292 | Rear Defog Switch Signal |
| B4 | RD/BK | 744 | Liftgate Ajar Switch Signal |
| B5 | D-GN | 392 | Rear Window Washer Pump Control |
| B6 | L-BU | 74 | Park Lamp Switch Signal (T82) |
| B7 | OG | 192 | Fog Lamp Switch Signal (T96) |
| B8 | Not Used | ||
| B9 | YE | 743 | Accessory Voltage |
| B10 | BN | 9 | Park Lamp Supply Voltage |
| B11 | L-GN | 1478 | Coolant Level Switch Signal |
| B12 | PU | 719 | Low Reference (Except HP7) |
Body Control Module (BCM) C2 Connector Terminal Identification
Scheme 12
| Connector Part Information OEM: 12110244 Service: See Catalog Description: 24-Way F Micro-Pack 100 Series (PK) |
Body Control Module (BCM) C3 Connector Parts Information
| Pin | Wire Color | Circuit No. | Function |
|---|---|---|---|
| A1 | WH | 156 | Dome Lamp Control |
| A2 | RD/WH | 812 | 12 Volt Reference |
| A3 | WH | 352 | Headlamp Relay Coil Supply Voltage (T82) |
| A4 | YE | 317 | Fog Lamp Relay Control (T96) |
| A5 | OG/BK | 1445 | Windshield Wiper Relay Control |
| A6 | RD | 2445 | Rear Wiper Relay Control |
| A7 | WH | 1080 | Park Lamp Relay Control (T82) |
| A8 | L-GN/BK | 592 | DRL Relay Control |
| A9 | BN/WH | 230 | I/P Lamps Dimming Control |
| A10 | PU | 1807 | Class 2 Serial Data |
| A11 | Not Used | ||
| A12 | TN | 2501 | CAN Low |
| B1 | TN/WH | 816 | A/T Shift Lock Switch Signal (A/T) |
| B2 | BK | 28 | Horn Relay Control |
| B3 | OG/BK | 1057 | Low Reference |
| B4 | GY | 112 | Windshield Wiper Switch Signal 1 |
| B5 | TN | 470 | Low Reference |
| B6 | WH | 193 | Rear Defog Relay Control |
| B7 | YE | 1836 | Security System Sensor Signal |
| B8 | D-GN | 113 | Windshield Wiper Switch Signal 2 |
| B9 | PU | 1807 | Class 2 Serial Data |
| B10 | PU | 1807 | Class 2 Serial Data |
| B11 | Not Used | ||
| B12 | TN/WH | 2500 | CAN High |
Body Control Module (BCM) C3 Connector Terminal Identification
Scheme 13
| Connector Part Information OEM: 12110626 Service: See Catalog Description: 8-Way F Metri-Pack 280 Series (GY) |
Body Control Module (BCM) C4 Connector Parts Information
| Pin | Wire Color | Circuit No. | Function |
|---|---|---|---|
| A | OG | 1732 | Courtesy Lamps Supply Voltage |
| B-C | Not Used | ||
| D | OG | 2540 | Battery Positive Voltage |
| E | GY | 8 | I/P Lamps Dimmer Switch Signal |
| F | BK/WH | 151 | Ground |
| G | Not Used | ||
| H | OG | 1640 | Battery Positive Voltage |
Body Control Module (BCM) C4 Connector Terminal Identification
Scheme 14
| Connector Part Information OEM: 348822-2 Service: See Catalog Description: 16-Way F Diangnostic Connector (BK) |
Data Link Connector (DLC) Connector Parts Information
| Pin | Wire Color | Circuit No. | Function |
|---|---|---|---|
| 1 | D-GN | 5060 | Low Speed GM LAN Serial Data (U32/U2K) |
| 2 | PU | 1807 | Class 2 Serial Data |
| 3 | Not Used | ||
| 4 | BK | 550 | Ground |
| 5 | BK/WH | 151 | Ground |
| 6 | TN/WH | 2500 | CAN High (HP7) |
| 7 | BN/WH | 2960 | Keyword Serial Data (Except HP7) |
| 8-11 | Not Used | ||
| 12 | WH/BK | 5043 | Keyword Serial Data (Except HP7) |
| 13 | Not Used | ||
| 14 | TN | 2501 | CAN Low (HP7) |
| 15 | Not Used | ||
| 16 | OG | 340 | Battery Positive Voltage |
Data Link Connector (DLC) Connector Terminal Identification
Test Description
The number below refers to the step number on the diagnostic table.
- 3: If DTC B1001 is set as current, reprogram the module.
| Step | Action | Yes | No |
|---|---|---|---|
| Connector End View Reference: Master Electrical Component List | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. Retrieve current DTCs with the scan tool. Is DTC B1001 retrieved as current? | Go to Step 3 | Go to Diagnostic Aids |
| 3 | Perform the programming or setup procedure for the module that set DTC B1001. Refer to Control Module References for the proper procedure. Does DTC 1001 reset? | Go to Step 4 | System OK |
| 4 | IMPORTANT: Perform the programming or setup procedure for the module. Replace the module that set DTC B1001. Refer to Control Module References for the proper procedure.Did you complete the replacement? | System OK | |
| IMPORTANT |
|---|
| Perform the programming or setup procedure for the module. |
DTC B1001
The numbers below refer to the step numbers on the diagnostic table.
- 2: A DTC U1001-U1254 Lost Communications with XXX with a history status may indicate the cause of U1000.
- 3: The modules not communicating are the likely cause of U1000. The modules that are available on the class 2 serial data circuit are listed in the Circuit Description.
- 7: The module which was not communicating due to a poor connection to the class 2 serial data circuit may have set DTC U1001-U1254 Lost Communications with XXX for those modules that it was monitoring.
- 10: 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.
- 13: If all modules are communicating, the module which set U1000 may have done so due to some other condition.
- 15: The module which set U1000 is the likely cause of the malfunction.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Communication Schematics Connector End View Reference: Data Communication Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. Record the DTCs set in 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? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3 |
| 3 | Turn ON the ignition, with the engine OFF. 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. Record all of the modules communicating on the class 2 serial data circuit. Compare the list of modules which are communicating to the list given in DLC description. Refer to Data Link Communications Description and Operation . Does any module on the class 2 serial data circuit not communicate? | Go to Step 4 | Go to Step 13 |
| 4 | Test the following circuits of the module that is not communicating for an open or short to ground: 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 Refer to the following: Control Module References for applicable schematics. Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Step 9 | Go to Step 5 |
| 5 | Turn OFF the ignition. Test the ground circuits of the module that is not communicating for an open. Refer to the following: Control Module References for applicable schematics. Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
| 6 | IMPORTANT: Inspect all connectors in the serial data communications circuit. Refer to the following: Testing for Intermittent Conditions and Poor Connections Connector Repairs Turn OFF the ignition. Test the class 2 serial data circuits of the module that is not communicating for an open. Refer to the following: Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
| 7 | Inspect the harness connector of the module that is not communicating for poor connections and terminal tension at the following circuits: The battery positive voltage input circuits The switched battery positive voltage supply The battery positive voltage output circuits The ignition voltage input circuits The ignition voltage output circuits The ground circuits The class 2 serial data circuits Refer to the following: Control Module References for applicable schematics. Testing for Intermittent Conditions and Poor Connections Connector Repairs Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
| 8 | Replace the module that is not communicating. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 11 | |
| 9 | Install a scan tool. Turn ON the ignition, with the engine OFF. 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"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 10 |
| 10 | Use the scan tool in order to clear the DTCs. Did you complete the action? | Go to Step 11 | |
| 11 | Select the Display DTCs function for the modules which had U1000 set as a current DTC. Does the scan tool display DTCs which do not begin with a "U"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 12 |
| 12 | Use the scan tool in order to clear the DTCs. Did you complete the action? | System OK | |
| 13 | Did you record any other DTCs for the modules which had U1000 set as a current DTC? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 14 |
| 14 | Install a scan tool. Turn ON the ignition, with the engine OFF. Use the scan tool in order to clear the DTCs. Turn OFF the ignition for at least 5 seconds. Turn ON the ignition with the engine OFF. Select the Display DTCs function. Does the scan tool display U1000 set as a current DTC? | Go to Step 15 | Go to Diagnostic Aids |
| 15 | Replace the module which had U1000 set as a current DTC. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | System OK | |
| IMPORTANT |
|---|
| Inspect all connectors in the serial data communications circuit. Refer to the following: Testing for Intermittent Conditions and Poor Connections Connector Repairs |
DTC U1000
The number below refers to the step number on the diagnostic table.
- 7: 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 Communication Schematics Connector End View Reference: Data Communication Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | IMPORTANT: Use the control module ID number list in order to determine which module is not communicating. Test the following circuits of the module that is not communicating for an open or a short to ground: The battery positive voltage input circuits The battery positive voltage output circuits The ignition voltage input circuits The ignition voltage output circuits The switched battery positive voltage circuits Refer to the following: Control Module References for applicable schematics. Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Step 7 | Go to Step 3 |
| 3 | Turn OFF the ignition. Test the ground circuits of the module that is not communicating for an open. Refer to the following: Control Module References for applicable schematics. Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Step 7 | Go to Step 4 |
| 4 | Test the class 2 serial data circuits of the module that is not communicating for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 7 | Go to Step 5 |
| 5 | Inspect the harness connectors of the module that is not communicating for poor connections and terminal tension at the following circuits: The battery positive voltage input circuits The battery positive voltage output circuits The ignition voltage input circuits The ignition voltage output circuits The switched battery positive voltage supply circuits The ground circuits The class 2 serial data circuits Refer to the following: Control Module References for applicable schematics Testing for Intermittent Conditions and Poor Connections Connector Repairs Did you find and correct the condition? | Go to Step 7 | Go to Step 6 |
| 6 | Replace the module that is not communicating. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 7 | |
| 7 | Install a scan tool. Turn ON the ignition with the engine OFF. 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"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 8 |
| 8 | 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"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 9 |
| 9 | Use the scan tool in order to clear the DTCs. Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared. Did you complete the action? | System OK | |
| IMPORTANT |
|---|
| Use the control module ID number list in order to determine which module is not communicating. |
DTC U1001-U1254
The number below refers to the step number on the diagnostic table.
- 4: If the battery positive voltage and ground circuits of the DLC are functioning properly, the malfunction must be due to the scan tool.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Communication Schematics Connector End View Reference: Data Communication Connector End Views | |||
| 1 | Test the battery positive voltage circuit of the data link connector (DLC) for an open or a short to ground. Refer to the following: Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle | Go to Step 2 |
| 2 | Test the ground circuits of the DLC for an open or high resistance. Refer to the following: Circuit Testing Wiring Repairs Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle | Go to Step 3 |
| 3 | Inspect for poor connections and terminal tension at the DLC. Refer to the following: Testing for Intermittent Conditions and Poor Connections Connector Repairs Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle | Go to Step 4 |
| 4 | The scan tool may be malfunctioning. Refer to the scan tool user guide. Did you obtain a properly operating scan tool? | Go to Diagnostic System Check - Vehicle | |
Scan Tool Does Not Power Up
The numbers below refer to the step numbers on the diagnostic table.
- 2: A partial loss of communication in the class 2 serial data circuit uses a different procedure than a total loss of communication of the class 2 serial data circuit.
- 4: The following DTCs may be retrieved with a history status. These DTCs are not the cause of the present condition. U1300 U1301
- 6: A State of Health DTC with a history status may be present along with a U1000 with a current status. This indicates that the malfunction occurred when the ignition was ON.
- 10: This step will isolate a wiring problem or a module malfunction.
- 12: This step analyzes the impact of each connected module to class 2 bus.
- 18: If there are no current DTCs that begin with the letter "U", the communication concern has been repaired.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Communication Schematics Connector End View Reference: Data Communication Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Turn ON the ignition, with the engine OFF. 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. Does the scan tool communicate with any module on the class 2 serial data circuit? | Go to Step 3 | Go to Step 8 |
| 3 | Select the Display DTCs function for each module. If using a Tech 2, use the Class 2 DTC Check feature in order to determine which modules do have DTCs set. Record all of the displayed DTCs, the DTC status, and the module which set the DTC. Did you record any DTCs in the range of U1000 to U1255? | Go to Step 4 | Go to Step 7 |
| 4 | Are history DTCs U1300 or U1301 retrieved from any module? | Go to Step 5 | Go to Step 6 |
| 5 | IMPORTANT: Turn ON the ignition, with the engine OFF, when testing for a short to voltage. Use the DMM MIN/MAX function to capture intermittent conditions. Test the class 2 serial data circuit for an intermittent short to ground or an intermittent short to voltage. Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Circuit Testing Connector Repairs Wiring Repairs Did you find and correct the condition? | Go to Step 17 | Go to Step 6 |
| 6 | Is U1000 the only DTC displayed in the previously specified range? | Go to DTC U1000 | Go to DTC U1001-U1254 |
| 7 | Diagnose the non communicating module by using the DTC U1001-U1254 Lost Communications with XXX procedure for the module which is not communicating. Refer to DTC U1001-U1254 . Did you complete the action? | Go to Diagnostic System Check - Vehicle | |
| 8 | Turn OFF the ignition. Disconnect the scan tool from the data link connector (DLC). Inspect for poor connections and terminal tension at the DLC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle | Go to Step 9 |
| 9 | Test the ground circuits of the DLC for an open or high resistance. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle | Go to Step 10 |
| 10 | Disconnect all modules on the class 2 serial data circuit. Test the class 2 serial data circuits between DLC and body control module (BCM), and between all disconnected modules for an open, a short to ground, or a short to voltage. Turn ON the ignition leaving the engine OFF when testing for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 11 |
| 11 | Turn OFF the ignition. Reconnect the BCM. Install the scan tool. Turn ON the ignition, with the engine OFF. Attempt to communicate with the BCM. Does the scan tool communicate with the BCM? | Go to Step Step 12 | Go to Step Step 13 |
| 12 | Continue connecting the disconnected modules one by one and attempt to communicate with BCM after each connection until communication can not be established or all modules are reconnected. When a module is connected, is communication lost with the class 2 serial data devices? | Go to Step 14 | Go to Diagnostic Aids |
| 13 | Inspect for poor connections and terminal tension at the class 2 serial data circuit of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 15 |
| 14 | Inspect for poor connections and terminal tension at the class 2 serial data circuit of the most recently reconnected module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 16 |
| 15 | Replace the BCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 17 | |
| 16 | Replace the most recently reconnected module. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 17 | |
| 17 | Connect all of the modules. Connect all the connectors. Install a scan tool. Turn ON the ignition, leaving the engine OFF. Wait for 10 seconds. Select the display DTCs function for each module. If using a Tech 2, use the Class 2 DTC Check feature in order to determine which modules do have DTCs set. Record all of the displayed DTCs and the DTC status. Did your record any DTCs which begin with a letter "U" and with a current status? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 18 |
| 18 | Did you record any DTCs which do not begin with a letter "U"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 19 |
| 19 | Clear the DTCs using the scan tool. Did you complete the action? | System OK | |
| IMPORTANT |
|---|
| Turn ON the ignition, with the engine OFF, when testing for a short to voltage. Use the DMM MIN/MAX function to capture intermittent conditions. |
Scan Tool Does Not Communicate with Class 2 Device
BCM Overview
The main features of the body control module (BCM) are
- The BCM is the gateway between the on class 2 serial data circuit and controller area network (CAN) serial data circuit.
- The BCM controls multiple functions.
- The BCM is the power mode master.