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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G3500, VAN PASSENGER EXTENDEDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 113 (DATA COMMUNICATION SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESSCAN TOOL DOES NOT COMMUNICATE WITH LOW SPEED GMLAN DEVICE (BUSS 1)CIRCUIT/SYSTEM TESTING
2008 Chevrolet Chevy Express G3500, Van Passenger Extended

Circuit/System Testing

2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, test for less than 1.0 ohm of resistance between the DLC ground circuit terminal 5 and ground.
    • If greater than specified, test the ground circuit for open/high resistance.
  2. Disconnect the X2 harness connector at the BCM.
  3. Install a 3Amp fused jumper wire between the BCM serial data circuit terminal 55 and the DLC terminal 1
  4. Ignition ON, attempt to communicate with the BCM. Communication should be available.
    IMPORTANT: Allow communications for 5 seconds after connecting a module with the jumper to determine if communication is interrupted or not.
    • If no communication, test the serial data circuit terminal 55 of the BCM for a short to ground, short to voltage, or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Ignition OFF, install a 3 Amp fused jumper wire between the BCM serial data circuit terminal 37 and the vehicle control interface module terminal 1
  6. Disconnect the X1 harness connector at the radio, if applicable.
  7. Ignition ON, attempt to communicate with the theft deterrent control module (TDM), communication should not be available.
    • If communication is established, test the radio serial data circuit terminal B10 for a short to voltage or a short to ground. If the circuit tests normal, replace the radio.
  8. Ignition OFF, disconnect the X2 harness connector at the HVAC control module, if applicable.
  9. Ignition ON, attempt to communicate with the TDM, communication should not be available.
    • If communication is established, test the HVAC control module serial data circuit terminal 1 for a short to voltage or a short to ground. If the circuit test normal, replace the HVAC control module.
  10. Ignition OFF, disconnect the harness connector at the TDM.
  11. Ignition ON, attempt to communicate with the instrument panel cluster (IPC), communication should not be available.
    • If communication is established, test the TDM serial data circuit terminal 6 for a short to voltage or a short to ground. If the circuit test normal, replace the TDM.
  12. Ignition OFF, disconnect the harness connector at the IPC.
  13. Ignition ON, attempt to communicate with the BCM, communication should not be available.
    • If communication is established, test the IPC serial data circuit terminal A8 for a short to voltage or a short to ground. If the circuit test normal, replace the IPC.
  14. Ignition OFF, disconnect the X3 harness connector at the VCIM, if applicable.
  15. Ignition ON, attempt to communicate with the BCM, communication should not be available.
    • If communication is established, test the VCIM serial data circuit terminal 7 for a short to voltage or a short to ground. If the circuit tests normal, replace the VCIM
  16. Ignition OFF, remove the 3 Amp fused jumper wire from the BCM terminal 37.
  17. Ignition ON, test for less then 1 volt between the BCM serial data circuit terminal 37 and ground.
    • If greater the specified range, test the serial data circuit for a short to voltage.
  18. Ignition OFF, test for less the 1 ohm between the BCM serial data circuit terminal 37 and ground.
    • If greater than the specified range, test the circuit for a short to ground.
  19. If all circuits test normal, replace the BCM.
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