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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 Chassis High Speed GMLAN Device >> Circuit/System Testing >> Testing the Serial Data Circuits for an Open/High Resistance (Data Bus Diagnostic Tool)
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Testing the Serial Data Circuits for an Open/High Resistance (Data Bus Diagnostic Tool)

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 chassis high speed GMLAN serial data circuits at the non responding device closest to the responding device.
  3. Disconnect the harness connectors with the chassis high speed GMLAN serial data circuits at the responding device closest to the non responding device.
  4. Test for less than 2 Ω in each of the chassis high speed GMLAN serial data circuits end to end between the two devices that was just disconnected.
    • If 2 Ω or greater 

      Repair the open/high resistance in the serial data circuit.

    • If less than 2 Ω 
  5. Replace the non responding device that was disconnected.