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Home >> Buick >> 2020 >> Encore Base >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Vehicle Access System >> Diagnostic Information and Procedures >> Liftgate Release Malfunction >> Circuit/System Testing

Circuit/System Testing

Test 1

    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. Disconnect the electrical connector: S46B Liftgate Unlatch Switch
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 2 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 2 @ Component harness & Ground Connection
      • 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. Ignition - On/Vehicle - In Service Mode
  5. Verify the scan tool parameter: Trunk Lid/Liftgate Window Exterior Unlatch Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 1 & Ground circuit terminal 2
  7. Verify the scan tool parameter: Trunk Lid/Liftgate Window Exterior Unlatch Switch = Active
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 1 @ Component harness & 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. Test for less than 2 ohms between the test points: Signal circuit terminal 1 @ Component harness & Terminal 15 X6 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  8. Test or replace the component: S46B Liftgate Unlatch Switch

Test 2

  1. Ignition/Vehicle - Off
  2. Remove the component: KR95A Liftgate Unlatch Relay
  3. Connect a test lamp between the test points: Control circuit terminal R2-1 & Ground
  4. Ignition - On/Vehicle - In Service Mode
  5. Perform the scan tool control function: Liftgate Unlatch - Unlatch

    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: X5 @ K9 Body Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal R2-1 @ 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 R2-1 @ Relay Socket & Terminal 20 X5 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: X5 @ K9 Body Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal R2-1 @ Relay Socket & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K9 Body Control Module
    • Go to next step: If the test lamp turns On and Off 
  6. Connect a test lamp between the test points: Control circuit terminal R2-2 & B+
  7. Perform the scan tool control function: Liftgate Unlatch - Unlatch

    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: X5 @ K9 Body Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal R2-2 @ 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. Test for less than 2 ohms between the test points: Control circuit terminal R2-2 @ Relay Socket & Terminal 11 X5 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: X5 @ K9 Body Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal R2-2 @ Relay Socket & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K9 Body Control Module
    • Go to next step: If the test lamp turns On and Off 
  8. Verify a test lamp turns On between the test points: B+ circuit terminal R2-3 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for less than 2 ohms between the test points: B+ circuit terminal R2-3 @ Relay Socket & Output terminal @ F13DA Fuse
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for infinite resistance between the test points: B+ circuit terminal R2-3 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Disconnect the electrical connector: M30 Liftgate Latch
    4. Test for infinite resistance between the test points: Control circuit terminal R2-5 @ Relay Socket & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    5. Replace the component: Fuse
    6. Install the component: KR95A Liftgate Unlatch Relay
    7. Connect a test lamp between the test points: Control circuit terminal 3 & Ground circuit terminal 1
    8. Ignition - On/Vehicle - In Service Mode
    9. Perform the scan tool control function: Liftgate Unlatch - Unlatch

      Verify the test lamp turns On and Off.

      • If the test lamp does not turn On and Off - Test or replace the component: KR95A Liftgate Unlatch Relay
      • If the test lamp turns On and Off - Test or replace the component: M30 Liftgate Latch
    • Go to next step: If the test lamp turns On 
  9. Momentarily connect a 10 A fused jumper wire between the test points: B+ circuit terminal R2-3 & Control circuit terminal R2-5

    Verify the component does not turn On and Off when connecting and disconnecting the jumper wire: M30 Liftgate Latch

    • If the component turns On and Off 

      Test or replace the component: KR95A Liftgate Unlatch Relay

    • Go to next step: If the component does not turn On and Off 
  10. Ignition/Vehicle & All vehicle systems - Off
  11. Install the component: KR95A Liftgate Unlatch Relay
  12. Disconnect the electrical connector: M30 Liftgate Latch
  13. Test for less than 10 ohms between the test points: Ground circuit terminal 1 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 1 @ Component harness & Ground Connection
      • 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 
  14. Connect a test lamp between the test points: Control circuit terminal 3 & Ground circuit terminal 1
  15. Ignition - On/Vehicle - In Service Mode
  16. Perform the scan tool control function: Liftgate Unlatch - Unlatch

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off 

      Repair the open/high resistance in the circuit: Control Circuit

    • If the test lamp is always On 

      Repair the short to voltage on the circuit: Control Circuit

    • Go to next step: If the test lamp turns On and Off 
  17. Test or replace the component: M30 Liftgate Latch
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