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Home >> Cadillac >> 2019 >> CT6 V >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls And Fuel - 4.2L (LTA) - Diagnostic Information And Procedures ( P0446-P349F) And Symptoms >> Diagnostic Information and Procedures >> DTC P2AB8, P2AB9, P2ABB, P2ABC, P2B81, P2B82, P2B93, P2B94, U0644, U0674, U1376, or U1377 >> Circuit/System Verification
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Circuit/System Verification

  1. Ignition - On / Vehicle - In Service Mode
  2. Verify DTC DTC P0641, P0651, P0697, or P06A3 is not set.
    • Go to next step: If none of the DTCs are set 
  3. Verify DTC P2AB8, P2AB9, P2ABB, P2ABC, U0644, U0674 is not set.
    • If only DTC P2AB8, P2AB9, P2ABB, P2ABC is set 

      Replace the appropriate component: M128A Turbocharger Wastegate Actuator - Bank 1/M128B Turbocharger Wastegate Actuator - Bank 2

    • If DTC U0644, U0674 and one or more of the DTCs P2AB8, P2AB9, P2ABB, P2ABC is set 

      Refer to: Circuit/System Testing

    • Go to next step: If none of the DTCs are set 
  4. Perform the appropriate scan tool control function: Turbocharger Wastegate Position Bank 1/Turbocharger Wastegate Position Bank 2 - Increase & Decrease

    Verify the appropriate scan tool parameter:

    • Turbocharger Wastegate Position Sensor Bank 1 = Desired Turbocharger Wastegate Position Bank 1
    • Turbocharger Wastegate Position Bank 2 = Desired Turbocharger Wastegate Position Bank 2
    • If not the specified state 

      Refer to: Circuit/System Testing

    • Go to next step: If the specified state 
  5. Verify the appropriate scan tool parameter: Turbocharger Wastegate Position Bank 1/Turbocharger Wastegate Position Bank 2 = The value should not spike or drop out.

    Perform the action while monitoring the parameter:

    • Wiggle the harness and connector: M128A Turbocharger Wastegate Actuator - Bank 1
    • Wiggle the harness and connector: M128B Turbocharger Wastegate Actuator - Bank 2
    • Wiggle the harness and connector: X1@K20 Engine Control Module
    • If the parameter value changes 

      Repair as necessary - Wiring / Terminal(s) / Electrical Connector(s)

    • Go to next step: If the parameter value does not change 
  6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

    • If the DTC sets 

      Refer to: Circuit/System Testing

    • Go to next step: If the DTC does not set 
  7. All OK.
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