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Home >> Buick >> 2019 >> Envision Base >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Battery, Starting System And Charging System >> Diagnostic Information and Procedures >> DTC B099A >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the S48A Multifunction Switch - Instrument Panel, ignition ON. It may take up to 2 min for all vehicle systems to power down.
  2. Connect a test lamp between the control circuit terminal 8 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 OFF 
    1. Ignition OFF, remove the test lamp, 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.
      • Go to next step: 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 is always ON 
    1. Ignition OFF, remove the test lamp, 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.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Connect a test lamp between the control circuit terminal 5 and ground.
  5. 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 OFF 
    1. Ignition OFF, remove the test lamp, 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.
      • Go to next step: If infinite resistance
    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 is always ON 
    1. Ignition OFF, remove the test lamp, 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, replace the K9 Body Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  6. Test or replace the S48A Multifunction Switch - Instrument Panel.
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