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Home >> Cadillac >> 2007 >> XLR Base >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Data Communication System >> Diagnostic Information and Procedures >> Scan Tool Does Not Communicate with Class 2 Device >> Test Description

Test Description

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

  1. 2:  A current DTC U1305 may be retrieved only from the body control module (BCM).
  2. 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. The BCM is diagnosed only through GMLAN serial data circuit.
    • Body control module (BCM)
    • Communication interface module (OnStar®)
    • Digital radio receiver (DRR)
    • Driver door module (DDM)
    • Driver door switch (DDS)
    • Driver position module (DPM)
    • Folding top controller (FTC)
    • Head up display (HUD)
    • HVAC control module
    • Inflatable restraint sensing and diagnostic module (SDM)
    • Instrument panel cluster (IPC)
    • Passenger door module (PDM)
    • Radio
    • Remote control door lock receiver (RCDLR)
    • Steering column lock control module (SCLCM)
  3. 7:  Data link connector terminals 2 and 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.
  4. 9:  A poor connection at splice pack SP205 will cause this condition but will not set a DTC.
  5. 10:  An open in the class 2 serial data circuit between the DLC and splice pack SP205 will prevent the scan tool from communicating with any module on the class 2 network. This condition will not set a DTC.
Scan Tool Does Not Communicate with Class 2 Device

Step Action Yes No
Schematic Reference: Data Communication Schematics 
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 
  1. Turn ON the ignition, with the engine OFF.
  2. Perform the Vehicle DTC Information function on the scan tool under Computer/Integrating Systems menu.
Are the DTCs U1300, U1301 or U1305 retrieved from any module?		 Go to DTC U1300, U1301 or U1305  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 7 
4 Did you record any DTCs in the range of U1000 to U1255? Go to Step 5  Go to Step 6 
5 Did you record any DTCs in the range of U1001 to U1254? Go to DTC U1001-U1254  Go to DTC U1000 and U1255 
6 Diagnose the non-communicating module by using the DTC U1001-U2154 procedure for the module which is not communicating. Refer to DTC U1001-U1254 .
Did you complete the action?		 Go to Diagnostic System Check - Vehicle -
7 
  1. Turn OFF the ignition.
  2. Disconnect the scan tool from the data link connector (DLC).
  3. Inspect for poor connections at the DLC terminals 2 and 5. 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 8 
8 Test the DLC ground circuit at terminal 5 for an open. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 Go to Diagnostic System Check - Vehicle Go to Step 9 
9 
  1. Disconnect the splice pack SP205.
  2. Inspect for poor connections at the splice pack SP205. 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  Repair the class 2 serial data circuit between the DLC and the splice pack SP205 for an open. Refer to Circuit Testing and Wiring Repairs .
Did you complete the action?		 System OK -
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