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Home >> Buick >> 2013 >> Verano Base >> Repair and Diagnosis (Single Page) >> Body & Frame >> Ignition Switch/Steering Lock >> Wiring Systems And Power Management - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> Power Mode Mismatch >> Circuit/System Testing

Circuit/System Testing

Diagnostic A

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR93 Ignition Run/Crank Relay. 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 85 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 30 and ground.
    • If the test lamp does not illuminate 

      Replace the X53A Fuse Block - Rear Body

    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
  6. Verify the test lamp turns ON and OFF when commanding the Run/Crank Relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the KR73 Ignition Main Relay and 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
    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.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the ignition circuit terminal 87 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit.

    • If the test lamp does not illuminate 
  8. Ignition ON, connect a 5 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit 87.
  9. Verify the device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  10. Test or replace the KR93 Ignition Run/Crank Relay.

Diagnostic B

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR73 Ignition Main Relay. 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 85 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 30 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
  6. Verify the test lamp turns ON and OFF when commanding the Run/Crank Relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the KR93 Ignition Run/Crank Relay and 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
    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.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the ignition circuit terminal 87 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit.

    • If the test lamp does not illuminate 
  8. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit 87.
  9. Verify the device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  10. Test or replace the KR73 Ignition Main Relay.

Diagnostic C

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR148 Steering Wheel Heater Relay. 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 85 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 30 and ground.
    • If the test lamp does not illuminate 

      Replace the X531 Fuse Block - Instrument Panel

    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
  6. Verify the test lamp turns ON and OFF when commanding the Auxiliary Ignition Run Relay On and Off 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.
      • 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.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the ignition circuit terminal 87 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit.

    • If the test lamp does not illuminate 
  8. Ignition ON, connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit 87.
  9. Verify the device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  10. Test or replace the KR148 Steering Wheel Heater Relay.

Diagnostic D

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR76 Retained Accessory Power Relay. 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 11 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 15 and ground.
    • If the test lamp does not illuminate 

      Replace the X51A Fuse Block - Instrument Panel

    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 13 and the ground circuit terminal 11.
  6. Verify the test lamp turns ON and OFF when commanding the Accessory/Retained Accessory Power relay On and Off 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.
      • 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.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the ignition circuit terminal 14 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit

    • If the test lamp does not illuminate 
  8. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 15 and the ignition circuit terminal 14.
  9. Verify device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  10. Test or replace the KR76 Retained Accessory Power Relay.

Diagnostic E

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR75 Engine Controls Ignition Relay, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • If the test lamp illuminates 
  3. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • If the test lamp illuminates 
  4. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  5. Verify the test lamp turns ON and OFF when cycling the ignition ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine 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. Ignition OFF.
    4. 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 K20 Engine Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine 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 K20 Engine Control Module.
    • If the test lamp turns ON and OFF 
  6. Verify a test lamp does not illuminate between the ignition circuit terminal 87 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the circuit.

    • If the test lamp does not illuminate 
  7. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87.
  8. Verify device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit terminal 87 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  9. Test or replace the KR75 Engine Controls Ignition Relay.
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