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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 123 (Engine Controls And Fuel - 3.6L (LF4) - Diagnostic Information And Procedures (3 Of 3)) >> Diagnostic Information and Procedures >> DTC P1516, P2101, P2119, or P2176 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle - Off
  2. NOTE:

    Disconnecting the component electrical connector causes additional DTCs to set.

  3. Disconnect the electrical connector: X25 @ Bank 1Valve Rocker Arm Cover
  4. Ignition - On / Vehicle - In Service Mode
  5. NOTE:

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

  6. Test for 8.5 to 10 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 ohms 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 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • If greater than 10 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 10 V 
  7. Ignition/Vehicle & All vehicle systems - Off
  8. NOTE:

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

  9. Use the special tool: EL-44603  Injector Test Lamp
  10. Connect the tool between the test points: Control circuit terminal 1 & Control circuit terminal 2
  11. Ignition - On / Vehicle - In Service Mode
  12. 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 ohms 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 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • Go to next step: If the test lamp flashes 
  13. Ignition/Vehicle - Off & Remove - Test lamp
  14. Remove - Charge Air Cooler Cover
  15. 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 
  16. Connect the electrical connector: X25 @ Bank 1Valve Rocker Arm Cover
  17. Disconnect the electrical connector: Q38 Throttle Body
  18. Use the special tool: EL-44603  Injector Test Lamp
  19. Connect the tool between the test points: Control circuit terminal 5 & Control circuit terminal 6
  20. Ignition - On / Vehicle - In Service Mode
  21. 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 
  22. Test or replace the component: Q38 Throttle Body