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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| Callout | Component Name |
|---|---|
| 1 | Cruise Control Actuator |
| 2 | Instrument Cluster |
| 3 | Cruise Control Module |
| 4 | Powertrain Control Module |
| 5 | Cruise Control Actuator Switch |
| 6 | Stop Lamp Switch |
| 7 | Data Link Connector |
| 8 | Park Neutral Position Switch |
Data Link Connector Connector Part Information 90980-11665 WH Pin Wire Color Function 1 - Not Used 2 PK Serial Data - Radio 3 - Not Used 4 WH/BK Ground 5 BN Ground 6 - Not Used 7 BL/RD Serial Data - On Star 8-10 - Not Used 11 BK/YE Serial Data 12 GY Serial Data 13 PK/BK Serial Data 14 - Not Used 15 PK Serial Data 16 RD/LK Battery Positive Voltage
Begin the system diagnosis with Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check - Vehicle will provide the following information
- The identification of the control modules which are not communicating.
- The identification of any stored diagnostic trouble codes (DTCs) and their status.
The use of the Diagnostic System Check - Vehicle will identify the correct procedures to begin vehicle diagnosis. These must be performed before system DTC or symptom diagnosis.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 1: A module which loses power during an ignition cycle will cause other modules to set Lost Communication DTCs.
- 2: A module which loses ground during an ignition cycle will cause other modules to set Lost Communication DTCs.
- 3: The malfunction is due to an open in the class 2 serial data circuit or an open in the module.
- 6: The module which was not communicating may have set Lost Communication DTCs for those modules that it was monitoring.
- 8: The modules which can communicate indicate the module which cannot communicate. You must clear the DTCs from these modules to avoid future misdiagnosis.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Link Connector (DLC) Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
| 1 | Test the battery positive voltage and ignition B+ circuits of the module that is not communicating for an open or a short to ground. Refer to the following: Circuit Testing in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 8 | Go to Step 2 |
| 2 | Turn OFF the ignition. Test the ground circuits of the module that is not communicating for an open. Refer to the following: Circuit Testing in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 8 | Go to Step 3 |
| 3 | Test the class 2 serial data circuit of the module that is not communicating for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 6 | Go to Step 4 |
| 4 | Inspect for poor connections at the battery positive voltage circuits, the ignition B+ circuits, the ground circuits, and the class 2 serial data circuit of the module that is not communicating. 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 6 | Go to Step 5 |
| 5 | Replace the module which is not communicating. Refer to Control Module References for replacement, setup and programming for the appropriate repair instructions. Did you complete the replacement? | Go to Step 8 | |
| 6 | Install a scan tool Turn ON the ignition leaving 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 System Check - Vehicle in Vehicle DTC Information | Go to Step 7 |
| 7 | Use the scan tool in order to clear the DTCs. Did you complete the action? | Go to Step 8 | |
| 8 | Select the Display DTCs function for the modules which had the Lost Communication with xxx DTC set. Does the scan tool display any DTCs which do not begin with a "U"? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | 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 | |
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 Link Connector (DLC) Schematics Connector End View Reference: Computer/Integrating Systems 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 in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 2 |
| 2 | Test the ground circuits of the DLC for an open or high resistance. Refer to the following: Circuit Testing in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | 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 in Wiring Systems Connector Repairs in Wiring Systems Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | 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 in Vehicle DTC Information | |
Scan Tool Does Not Power Up
The numbers below refer to the step numbers on the diagnostic table.
- 3: A partial malfunction in the class 2 serial data circuit uses a different procedure from a total malfunction of the class 2 serial data circuit. The following modules communicate on the class 2 serial data circuit. Communication interface module (OnStar®) Electronic brake control module (EBCM) Inflatable restraint sensing and diagnostic module (SDM) Instrument panel cluster (IPC) Radio
- 5: DLC terminals 2 and 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.
- 7: A poor connection at splice pack S232 will cause this condition but will not set a DTC.
- 8: An open in the class 2 serial data circuit between the DLC and splice pack S232 will prevent the scan tool from communicating with any module on the class 2 network. This condition will not set a DTC.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Link Connector (DLC) Schematics Connector End View Reference: 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 in Vehicle DTC Information |
| 2 | Turn ON the ignition, with the engine OFF. Perform the Vehicle DTC Information function on the scan tool under Computer/Integrating Systems menu. Are any DTC's retrieved from any module? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
| 3 | Did the scan tool communicate with any module on the class 2 serial data circuit? | Go to Step 4 | Go to Step 5 |
| 4 | Diagnose the non-communicating module by referring to the appropriate section. Did you complete the action? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 5 | Turn OFF the ignition. Disconnect the scan tool from the data link connector (DLC). Inspect for poor connections at the DLC terminals 2 and 5. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 6 |
| 6 | Test the DLC ground circuit at terminal 5 for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 7 |
| 7 | Disconnect the splice pack S232. Inspect for poor connections at the splice pack SP205. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 8 |
| 8 | Repair the class 2 serial data circuit between the DLC and the splice pack S232 for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the action? | System OK | |
Scan Tool Does Not Communicate with Class 2 Device
The numbers below refer to the step numbers on the diagnostic table.
- 3: A partial malfunction in the serial data circuit uses a different procedure from a total malfunction of the serial data circuit. The following modules communicate on the serial data circuit. Communication interface module (OnStar®) Electronic brake control module (EBCM) Inflatable restraint sensing and diagnostic module (SDM) Instrument panel cluster (IPC) Radio
- 5: DLC terminals 2 and 5 provide the connection to the serial data circuit and the signal ground circuit respectively.
- 7: A poor connection at splice pack S232 will cause this condition but will not set a DTC.
- 8: An open in the serial data circuit between the DLC and splice pack S232 will prevent the scan tool from communicating with any module on the network. This condition will not set a DTC.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Link Connector (DLC) Schematics Connector End View Reference: 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 in Vehicle DTC Information |
| 2 | Turn ON the ignition, with the engine OFF. Perform the Vehicle DTC Information function on the scan tool under Computer/Integrating Systems menu. Are any DTC's retrieved from any module? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
| 3 | Did the scan tool communicate with any module on the serial data circuit? | Go to Step 4 | Go to Step 5 |
| 4 | Diagnose the non-communicating module by referring to the appropriate section. Did you complete the action? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 5 | Turn OFF the ignition. Disconnect the scan tool from the data link connector (DLC). Inspect for poor connections at the DLC terminals 2 and 5. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 6 |
| 6 | Test the DLC ground circuit at terminal 5 for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 7 |
| 7 | Disconnect the splice pack S232. Inspect for poor connections at the splice pack SP205. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | Go to Step 8 |
| 8 | Repair the serial data circuit between the DLC and the splice pack S232 for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the action? | System OK | |
Scan Tool Does Not Communicate with Keyword Data Line
Data Link Communications Description and Operation
The scan tool accesses the following data lines
- The brake pressure control valve (BPMV)-On vehicles with antilock brake systems.
- The powertrain control module (PCM)
- The inflatable restraint sensing and diagnostic control module (SDM)
- The radio.
The BLU/RED wire at cavity 7 of the data link connector (DLC) provides access to the BPMV, SDM, and to the PCM and the radio. The RED/BLK wire at cavity 16 provides voltage to the scan tool. The WHT/BLK wire at cavity 4 and the BRN/RED wire at cavity 5 provides ground to the scan tool.
The data lines monitor the module for diagnostic purposes and for diagnostic trouble codes (DTCs).