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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 41 (Wiring Systems And Power Management - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Power Mode Mismatch >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

Diagnostic A

  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 85 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF/Vehicle 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.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  4. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate 

      Replace the X51A Fuse Block - Instrument Panel

    • Go to next step: 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 cycling the vehicle between ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K84 Keyless Entry 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 K84 Keyless Entry Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K84 Keyless Entry Control Module, ignition ON/Vehicle in Service Mode.
    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 K84 Keyless Entry Control Module.
    • Go to next step: 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

    • Go to next step: If the test lamp does not illuminate 
  8. Ignition ON/Vehicle in Service Mode, connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87.
  9. Verify device is activated.
    • If the device does not activate 
    1. Ignition OFF/Vehicle 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.
      • Go to next step: 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.
    • Go to next step: If the device activates 
  10. Test or replace the KR76 Retained Accessory Power Relay.

Diagnostic B

  1. Ignition OFF/Vehicle 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/Vehicle 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.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  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

    • Go to next step: 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/Vehicle 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/Vehicle OFF and all vehicle systems OFF, remove the test lamp, disconnect the K9 Body Control Module, ignition ON/Vehicle in Service Mode.
    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 
  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

    • Go to next step: If the test lamp does not illuminate 
  8. Ignition ON/Vehicle in Service Mode, connect a 40 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87.
  9. Verify the device is activated.
    • If the device is not activated 
    1. Ignition OFF/Vehicle 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.
      • Go to next step: 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.
    • Go to next step: If the device activates 
  10. Test or replace the KR73 Ignition Main Relay.

Diagnostic C

  1. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the KR75 Engine Controls Ignition Relay, ignition ON/Vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 87 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • Go to next step: 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

    • Go to next step: 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 switching the vehicle ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module, ignition ON/Vehicle in Service Mode.
    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. Ignition OFF/Vehicle 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/Vehicle OFF, remove the test lamp, 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.
    • Go to next step: If the test lamp turns ON and OFF 
  6. Verify a test lamp does not illuminate between the ignition circuit terminal 30 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the circuit.

    • Go to next step: If the test lamp does not illuminate 
  7. Ignition ON/Vehicle in Service Mode, connect a 40 A fused jumper wire between the B+ circuit terminal 87 and the ignition circuit terminal 30.
  8. Verify device is activated.
    • If the device is not activated 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit terminal 30 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 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.
    • Go to next step: If the device activates 
  9. Test or replace the KR75 Engine Controls Ignition Relay.
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