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Home › GMC › 2017 › Acadia SL › Repair and Diagnosis › External Pages › Different car › Section 180 (Battery, Charging System And Starting System) › Diagnostic Information and Procedures › DTC B099A: Stop/Start Select Switch Indicator Circuit › Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the S48A Multifunction Switch 2 - Instrument Panel, ignition ON.
  2. Connect a test lamp between the control circuit terminal 4 and B+.
  3. Verify the test lamp turns ON and OFF when commanding the Start/Stop Select Switch Indicator Active and Inactive with a scan tool.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp illuminates 
  4. Test or replace the S48A Multifunction Switch 2 - Instrument Panel.
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