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Home >> Chevrolet >> 2014 >> Captiva Sport LS >> Repair and Diagnosis >> Engine Performance >> System >> Data Communication System >> Diagnostic Information and Procedures >> DTC U2105-U2199 (Except U2142 and U2143): Lost Communication with Control Module >> Circuit/System Testing

Circuit/System Testing

NOTE:

Use the schematic to identify the following:

  • Control modules the vehicle is equipped with
  • Control module locations on the low and high speed GMLAN serial data circuits
  • The control modules B+, ignition, ground, accessory wakeup serial data, serial data communication enable and serial data circuit terminals
  1. Ignition OFF, disconnect the harness connector at the control module that is not communicating.
  2. Test for less than 10 Ω between each ground circuit terminal and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. If equipped, ignition ON, verify that a test lamp illuminates between each B+ circuit terminal and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the control circuits of the control module for a short to ground. If the circuits test normal, replace the control module.
  4. If equipped, ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the control circuits of the control module for a short to ground. If the circuits test normal, replace the control module.
    5. NOTE:

    Only the high speed GMLAN modules have a serial data communication enable circuit OR an accessory wakeup serial data circuit and the body control module is the output for these circuits. Refer to the control module schematics to identify which control modules have these circuits.

  5. If equipped, ignition ON, verify that a test lamp illuminates between the serial data communication enable circuit terminal OR the accessory wakeup circuit terminal and ground.
    • If the test lamp does not illuminate, test the entire circuit, including the B+ circuit to the K9 body control module (BCM), for an open/high resistance or short to ground. If the circuits test normal, replace the K9 BCM.
  6. Ignition OFF for 60 seconds, test for less than 5 Ω between the serial data circuit terminals and the appropriate X84 data link connector (DLC) terminal listed below:
    • Low speed GMLAN serial data terminal 1
    • High speed GMLAN serial data terminal 6 or 14
    • If greater than the specified range, test the serial data circuit for an open/high resistance between the non communicating control module and the control module setting the DTC or a serial data splice pack.
  7. If all circuits test normal, replace the control module that is not communicating.
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