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Home >> Cadillac >> 2015 >> ATS Base, 2D Coupe, AWD >> Repair and Diagnosis >> Electrical >> Charging Systems >> Battery, Charging System And Starting System >> Diagnostic Information and Procedures >> Stop/Start System Malfunction >> Circuit/System Testing
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Circuit/System Testing

ECO Switch Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the S48A Multifunction Switch - Instrument Panel ignition ON.
  2. Verify the scan tool Stop/Start Select Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit terminal 10 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 Inactive 
  3. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground.
  4. Verify the scan tool Stop/Start Select Switch parameter is Active.
    • If not Active 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF.
    4. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If Active 
  5. Test or replace the S48A Multifunction Switch - Instrument Panel.

ECO Switch Indicator Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the S48A Multifunction Switch - 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 signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  4. Test or replace the S48A Multifunction Switch - Instrument Panel.

Power Supply Transformer Circuit Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the T19 Power Supply Transformer. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 1 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground.
    • If the test amp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for infinite resistance between the T19 Power Supply Transformer control circuit terminal 4 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test or replace the T19 Power Supply Transformer.
      • If the test lamp illuminates 
  5. Verify a test lamp illuminates between the ignition circuit terminal 5 and ground.
    • If the test lamp does not illuminate 
    1. Ignition OFF.
    2. Test for infinite resistance between the ignition circuit and ground.
    • If the test lamp illuminates 
  6. Test or replace the T19 Power Supply Transformer.
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