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Home >> Cadillac >> 2021 >> CT5 Sport, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 6 (Engine Controls And Fuel - 3.0L (LGY) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> DTC P1516, P2101, P2119, or P2176 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle - Off
    2. NOTE:

    Disconnecting the component electrical connector causes additional DTCs to set.

  2. Disconnect the electrical connector: X25 @ Charge Air Cooler Cover
  3. Ignition - On / Vehicle - In Service Mode
    4. NOTE:

    Testing for steps 4 to 9 is performed on the control module K20 side of the harness connector.

  4. Test for 8.5 to 9.5 V between the test points:
    • Control circuit terminal 1 & Ground
    • Control circuit terminal 2 & Ground
    • If less than 8.5 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control circuit terminal 2 @ Component harness & 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 Ω between the test points:
      • Control circuit terminal 1 @ Component harness & The other end of the circuit @ Control module harness
      • Control circuit terminal 2 @ Component harness & The other end of the circuit @ Control module harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω - Replace the component: K20 Engine Control Module
    • If greater than 9.5 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate 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 1 @ Component harness & Ground
      • Control circuit terminal 2 @ Component harness & 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 between 8.5 and 9.5 V 
  5. Ignition/Vehicle & All vehicle systems - Off
    6. NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate test can be performed.

  6. Use the special tool: EL-44603 Injector Test Lamp
  7. Connect the tool between the test points: Control circuit terminal 1 & Control circuit terminal 2
  8. Ignition - On / Vehicle - In Service Mode
  9. Verify the test lamp flashes - Once
    • If the test lamp does not flash 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: K20 Engine Control Module
    3. Test for less than 2 Ω between the test points:
      • Control circuit terminal 1 @ Component harness & The other end of the circuit @ Control module harness
      • Control circuit terminal 2 @ Component harness & The other end of the circuit @ Control module harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω - Replace the component: K20 Engine Control Module
    • Go to next step: If the test lamp flashes 
  10. Ignition/Vehicle - Off & Remove - Test lamp
  11. Remove - Charge Air Cooler Cover
  12. Verify a condition does not exist with the component: Blade @ Q38 Throttle Body
    • Binding or Sticking @ Open/Closed
    • Closed @ Engine Off
    • Coking / Debris / Dirty / Visible Damage
    • Open/Closed - Without spring pressure
    • If a condition exists 

      Replace the component: Q38 Throttle Body

    • Go to next step: If no condition exists 
  13. Connect the electrical connector: X25 @ Charge Air Cooler Cover
  14. Disconnect the electrical connector: Q38 Throttle Body
  15. Use the special tool: EL-44603 Injector Test Lamp
  16. Connect the tool between the test points: Control circuit terminal 5 & Control circuit terminal 6
  17. Ignition - On / Vehicle - In Service Mode
  18. Verify the test lamp flashes - Once
    • If the test lamp does not flash 

      Test or replace the component: Jumper Harness @ Q38 Throttle Body

    • Go to next step: If the test lamp flashes 
  19. Test or replace the component: Q38 Throttle Body
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