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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 10 (Automatic Transmission - VT40 (MRG) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0964-P0968, P0970, P0971, P2670, P2671, P2727, P2729, or P2730 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector:X1 @ T12 Automatic Transmission Assembly
  3. Connect a test lamp between the test points:Control circuit terminal 25 & Ground
  4. Ignition - On / Vehicle - In Service Mode
  5. Perform the scan tool control function:High Side Driver 2 - On and Off

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off 
    1. Connect the electrical connector:X1 @ T12 Automatic Transmission Assembly
    2. Ignition/Vehicle - Off
    3. Disconnect the electrical connector:
      • K71 Transmission Control Module
      • X1 @ T12 Automatic Transmission Assembly
    4. Test for infinite resistance between the test points:Control circuit terminal 25 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    5. Test for less than 2 ohms between the test points:Control circuit terminal 25 @ 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:K71 Transmission Control Module
    • If the test lamp is always On 
    1. Connect the electrical connector:X1 @ T12 Automatic Transmission Assembly
    2. Ignition/Vehicle - Off
    3. Disconnect the electrical connector:
      • K71 Transmission Control Module
      • X1 @ T12 Automatic Transmission Assembly
    4. Ignition - On / Vehicle - In Service Mode
    5. Test for less than 1 V between the test points:Control circuit terminal 25 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component:K71 Transmission Control Module
    • Go to next step: If the test lamp turns On and Off 
  6. Connect the electrical connector: X1 @ T12 Automatic Transmission Assembly
  7. Verify DTC P2670, P2671 is not set.
    • If the DTC is set 

      Refer to step 14

    • Go to next step: If the DTC is not set 
  8. Ignition/Vehicle - Off
  9. Disconnect the electrical connector:
    • K71 Transmission Control Module
    • X1 @ T12 Automatic Transmission Assembly
  10. Test for less than 2 ohms between the test points:
    • { P0964 - P0967 }Control circuit terminal 26 @ Component harness & The other end of the circuit @ Control module harness
    • { P0968, P0970, P0971 }Control circuit terminal 24 @ Component harness & The other end of the circuit @ Control module harness
    • { P2727, P2729, P2730 }Control circuit terminal 14 @ Component harness & The other end of the circuit @ Control module harness
    • If 2 ohms or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 ohms 
  11. Test for infinite resistance between the test points:
    • { P0960 - P0963 } Control circuit terminal 26 @ Component harness & Ground
    • { P0968, P0970, P0971 } Control circuit terminal 24 @ Component harness & Ground
    • { P2736 - P2739 } Control circuit terminal 14 @ Component harness & Ground
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  12. Ignition - On / Vehicle - In Service Mode
  13. Test for less than 1 V between the test points:
    • { P0960 - P0963 } Control circuit terminal 26 @ Component harness & Ground
    • { P0968, P0970, P0971 } Control circuit terminal 24 @ Component harness & Ground
    • { P2736 - P2739 } Control circuit terminal 14 @ Component harness & Ground
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  14. Ignition/Vehicle - Off
  15. Remove the component:Transmission Cover
  16. Connect the electrical connector:X1 @ T12 Automatic Transmission Assembly
  17. Disconnect the appropriate electrical connector:Q77 Transmission Control Solenoid Valve
  18. Connect a test lamp between the test points:Control circuit terminal 1 & Ground
  19. Ignition - On / Vehicle - In Service Mode
  20. Perform the scan tool control function:High Side Driver 2 - On and Off

    Verify the test lamp turns On and Off.

    • If the test lamp does not turn On and Off 

      Replace the component:Automatic Transmission Wiring Harness

    • Go to next step: If the test lamp turns On and Off 
  21. Test for less than 2 ohms between the test points:Control circuit terminal 2 @ Component harness & The other end of the circuit @ Control module harness
    • If 2 ohms or greater 

      Replace the component:Automatic Transmission Wiring Harness

    • Go to next step: If less than 2 ohms 
  22. Test for infinite resistance between the test points:Control circuit terminal 2 @ Component harness & Ground
    • If less than infinite resistance 

      Replace the component:Automatic Transmission Wiring Harness

    • Go to next step: If infinite resistance 
  23. Test or replace the component:Q77 Transmission Control Solenoid Valve
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