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Home >> GMC >> 2021 >> Acadia SL >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Battery, Starting System And Charging System - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P3051, P3053, or P3055 >> Circuit/System Testing - T19 Power Supply Transformer Input/Output Circuit Test

Circuit/System Testing - T19 Power Supply Transformer Input/Output Circuit Test

NOTE:

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

    NOTE:

    Do not replace the T19 Power Supply control module if you cannot reproduce the codes during a drive cycle.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: T19 Power Supply Transformer
  3. Test for less than 2 ohms between the test points:
    • Ground circuit terminal 7 @ T19 Power Supply Transformer & Ground
    • Ground circuit terminal 12 @ T19 Power Supply Transformer & Ground
    • If 2 ohms or greater 
    1. Disconnect the appropriate ground connection:
    2. Test for less than 0.5 ohms between the test points: Each ground circuit terminal @ T19 Power Supply Transformer & The other end of the circuit
      • If 0.5 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 0.5 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 2 ohms 
  4. Verify a test lamp turns On between the test points: 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 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 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. Ignition - On / Vehicle - In Service Mode
  6. 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 
  7. Ignition Off
  8. Verify a test lamp does not turn On between the test points: Ignition circuit terminal 6 @ T19 Power Supply Transformer & Ground
    • If the test lamp turns On 

      Repair the short to voltage on the circuit.

    • Go to next step: If the test lamp does not turn On 
  9. Ignition - On / Vehicle - In Service Mode
  10. Verify a test lamp does not turn on between terminal 10 and ground.
    • If the test lamp turns On 

      Repair the short to voltage on circuit 2172.

    • Go to next step: If the test lamp does not turn On 
  11. Remove all appropriate fuses supplied by circuit 2172.
  12. Test for infinite resistance between Terminal 10 at the T19 Power Supply Transformer and ground.
      NOTE:

      A less than infinite reading can be caused by component circuits being shorted to another component within the harness or a slight chafe to grounds preventing a fuse to open.

    • If less than infinite 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  13. Replace the T19 Power Supply Transformer.
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