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Home >> Chevrolet >> 2021 >> Malibu LT >> Repair and Diagnosis >> Electrical >> Starter >> 12 V Starting And Charging - Diagnostic Information And Procedures (1 Of 2) >> Diagnostic Information and Procedures >> DTC P305D or P305E >> Circuit/System Testing

Circuit/System Testing

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Remove the component: KR27 Starter Relay
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 85 & Ground
    • If 10 ohms or greater 
    1. Disconnect the ground connection:
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 85 & The other end of the circuit
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  4. Connect a test lamp between the test points: Control circuit terminal 86 & Ground circuit terminal 85
  5. Ignition - On/Vehicle - In Service Mode
  6. Perform the appropriate scan tool control function:
    • {If available} Starter Motor Relay - On and Off
    • {If available} Starter Relay - On and Off
  7. Verify the test lamp turns On and Off.
    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: Each component on the circuit
    3. Test for infinite resistance between the test points: Control circuit terminal 86 @ Relay Socket & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Control circuit terminal 86 @ Relay Socket & Control circuit terminal @ Control module harness - K20 Engine Control Module
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: Each component on the circuit
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 86 @ Relay Socket & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Connect the component: T19 Power Supply Transformer
    7. Ignition - On/Vehicle - In Service Mode
    8. Test for less than 1 V between the test points: Control circuit terminal 86 @ Relay Socket & Ground
      • If 1 V or greater

        Replace the component: T19 Power Supply Transformer

      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If the test lamp turns On and Off 
  8. Connect a test lamp between the test points: Control circuit terminal 5 @ T19 Power Supply Transformer & B+
  9. Ignition - On/Vehicle - In Service Mode
  10. Perform the appropriate scan tool control function:
    • {If available} Starter Motor Relay - On and Off
    • {If available} Starter Relay - On and Off
  11. Verify the test lamp turns On and Off.
    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 5 @ T19 Power Supply Transformer & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Control circuit terminal 5 @ T19 Power Supply Transformer & Control circuit terminal @ Control module harness - K20 Engine Control Module
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 5 @ T19 Power Supply Transformer & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If the test lamp turns On and Off 
  12. Replace the component: T19 Power Supply Transformer
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