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Home >> Buick >> 2018 >> Envision Base >> Repair and Diagnosis >> Electrical >> Charging Systems >> Battery, Charging System And Starting System >> Diagnostic Information and Procedures >> DTC P3051, P3053, or P3055 >> Circuit/System Testing

Circuit/System Testing

NOTE:

Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: T19 Power Supply Transformer
  3. Test for less than 10 ohms between the test points:
    • Ground circuit terminal 7 @ T19 Power Supply Transformer & Ground
    • Ground circuit terminal 12 @ T19 Power Supply Transformer & Ground
    • If 10 ohms or greater 
    1. Disconnect the appropriate ground connection:
    2. Test for less than 2 ohms between the test points: Each ground circuit terminal @ T19 Power Supply Transformer & 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. Verify a test lamp turns On between the test points:
    • B+ circuit terminal 8 @ T19 Power Supply Transformer & Ground
    • B+ circuit terminal 11 @ T19 Power Supply Transformer & 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 8 @ T19 Power Supply Transformer & Output terminal @ Fuse
      • B+ circuit terminal 11 @ T19 Power Supply Transformer & Output terminal @ 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 8 @ T19 Power Supply Transformer & Ground
      • B+ circuit terminal 11 @ T19 Power Supply Transformer & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: T19 Power Supply Transformer
    • Go to next step: If the test lamp turns On 
  5. Verify a test lamp turns On between the test points: Ignition circuit terminal 6 @ T19 Power Supply Transformer & 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: Ignition circuit terminal 6 @ T19 Power Supply Transformer & KR73 Ignition Main Relay
      • 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: Ignition circuit terminal 6 @ T19 Power Supply Transformer & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: T19 Power Supply Transformer
    • Go to next step: If the test lamp turns On 
  6. Ignition/Vehicle - Off & Remove - Test lamp
  7. Connect all electrical connectors.
  8. Clear DTCs
  9. Operate the vehicle under the following conditions: Autostart/Autostop
  10. Verify DTC P3051, P3053, P3055 is not set.
    • If any of the DTCs are set 

      Test or replace the component: T19 Power Supply Transformer

    • Go to next step: If no DTC is set 
  11. All OK.
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