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Home >> Chevrolet >> 2016 >> Spark LS, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 23 (Data Communication System) >> Diagnostic Information and Procedures >> Scan Tool Does Not Communicate with High Speed GMLAN Device >> Circuit/System Testing >> Testing the Serial Data Circuits for a Short between the Circuits
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Testing the Serial Data Circuits for a Short between the Circuits

WARNING: This page is about a different car, the 2015 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, all access doors closed, all vehicle systems OFF and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 2 min for all vehicle systems to power down.
  2. Disconnect the harness connectors with the high speed GMLAN serial data circuits at an easily accessible device that is not communicating.
  3. Test for greater than 110 Ω between each pair of serial data circuits at the device connector that was just disconnected.
    • If each pair of serial data circuits is 110 Ω or greater 

      Replace the device that was disconnected.

    • If any pair of serial data circuits is less than 110 Ω 
  4. Connect the harness connectors at the device that was disconnected.
  5. Disconnect the harness connectors with the high speed GMLAN serial data circuits at another device, in the direction of the circuit shorted together.
  6. Test for greater than 110 Ω between each pair of serial data circuits at the device connector that was just disconnected.
    • If each pair of serial data circuits is 110 Ω or greater 

      Replace the device that was disconnected.

    • If any pair of serial data circuits is less than 110 Ω 
  7. Repeat step 4 until one of the following conditions are isolated:
    • Serial data circuits shorted together between two devices or splice packs, if equipped.
    • Serial data circuits shorted together between a device and a terminating resistor.
    • Serial data circuits shorted together between the X84 Data Link Connector and the first device or splice pack.
    • A shorted terminating resistor.