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Home >> Chevrolet >> 2021 >> Trailblazer RS, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Automatic Transmission - VT40 (MRG) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0658, P0659, P0960, P0962, P0963, P2718, P2720, P2721, P2736, P2738, or P2739 >> Circuit/System Testing

Circuit/System Testing

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

    To turn the ignition off on vehicles equipped with a push button ignition switch, the wiring harness connector must be connected to the component T12.A valid park input signal to the control module K71 is required to turn the ignition off.

  2. Disconnect the electrical connector: X1 @ T12 Automatic Transmission Assembly
  3. Connect a test lamp between the test points: Control circuit terminal 15 & Ground
  4. Ignition - On / Vehicle - In Service Mode
  5. Perform the scan tool control function: High Side Driver 1 - On and Off

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:
      • K71 Transmission Control Module
      • X1 @ T12 Automatic Transmission Assembly
    3. Test for infinite resistance between the test points: Control circuit terminal 15 @ 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 15 @ 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. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:
      • K71 Transmission Control Module
      • X1 @ T12 Automatic Transmission Assembly
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 15 @ 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. Verify DTC P0658, P0659 is not set.
    • If the DTC is set 

      Refer to step 14

    • Go to next step: If the DTC is not set 
  7. Ignition/Vehicle - Off
  8. Disconnect the electrical connector:
    • K71 Transmission Control Module
    • X1 @ T12 Automatic Transmission Assembly
  9. Test for less than 2 ohms between the test points:
    • {P0960, P0962, P0963} Control circuit terminal 5 @ Component harness & The other end of the circuit @ Control module harness
    • {P2718, P2720, P2721} Control circuit terminal 3 @ Component harness & The other end of the circuit @ Control module harness
    • {P2736, P2738, P2739} Control circuit terminal 4 @ 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 
  10. Test for infinite resistance between the test points:
    • {P0960, P0962, P0963} Control circuit terminal 5 @ Component harness & Ground
    • {P2718, P2720, P2721} Control circuit terminal 3 @ Component harness & Ground
    • {P2736, P2738, P2739} Control circuit terminal 4 @ Component harness & Ground
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  11. Ignition - On / Vehicle - In Service Mode
  12. Test for less than 1 V between the test points:
    • {P0960, P0962, P0963} Control circuit terminal 5 @ Component harness & Ground
    • {P2718, P2720, P2721} Control circuit terminal 3 @ Component harness & Ground
    • {P2736, P2738, P2739} Control circuit terminal 4 @ 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 
  13. Ignition/Vehicle - Off
  14. Remove the component: Transmission Cover
  15. Connect the electrical connector: X1 @ T12 Automatic Transmission Assembly
  16. Disconnect the appropriate electrical connector: Q77 Transmission Control Solenoid Valve
  17. Connect a test lamp between the test points: Control circuit terminal 1 & Ground
  18. Ignition - On / Vehicle - In Service Mode
  19. Perform the scan tool control function: High Side Driver 1 - 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 
  20. 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 
  21. 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 
  22. Test or replace the component: Q77 Transmission Control Solenoid Valve
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