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Home >> Chevrolet >> 2022 >> Tahoe PPV, RWD >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission - 10L80 (MHS MQC) - Diagnostic Information And Procedures (1 Of 2) >> Diagnostic Information and Procedures >> DTC P0960, P0962-P0964, P0966-P0968, P0970, P0971, P2670, P2671, P2718, P2720, P2721, P2727, P2729, P2730, P2736, P2738, P2739, P2824, P2826, or P2827 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition/Vehicle - Off
    2. NOTE:

    When the following connector is disconnected, the ignition cannot be turned off due to lack of a valid park input to the TCM. If the ignition needs to be turned off, the connector will need to be reconnected.

  2. Disconnect the electrical connector: X1 @ T12 Automatic Transmission
  3. Connect a test lamp between the test points: Control circuit terminal 9 @ Component harness & Ground
  4. Ignition - On / Vehicle - In Service Mode
    5. NOTE:

    If unable to perform the scan tool control function due to Device Limits Exceeded and/or DTC Present, jumper the component B14A circuits between the component T12 connector and the X1 harness connector.

    • Connect a 3 A fused jumper wire between the test points: 9 V Reference circuit terminal 7 X1 (harness side) & 9 V Reference circuit terminal 7 X1 (component side)
    • Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 4 X1 (harness side) & Signal circuit terminal 4 X1 (component side)
  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. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 9 @ 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 9 @ 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
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 9 @ 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 P2670, P2671 is not set.
    • If the DTC is set 

      Refer to step 9

    • Go to next step: If the DTC is not set 
  7. Connect a test lamp between the test points:
    • { P0960, P0962, P0963 } Control circuit terminal 14 & Control circuit terminal 9 @ Component harness
    • { P0964, P0966, P0967 } Control circuit terminal 15 & Control circuit terminal 9 @ Component harness
    • { P0968, P0970, P0971 } Control circuit terminal 16 & Control circuit terminal 9 @ Component harness
    • { P2718, P2720, P2721 } Control circuit terminal 21 & Control circuit terminal 9 @ Component harness
    • { P2727, P2729, P2730 } Control circuit terminal 22 & Control circuit terminal 9 @ Component harness
    • { P2736, P2738, P2739 } Control circuit terminal 23 & Control circuit terminal 9 @ Component harness
    • { P2824, P2826, P2827 } Control circuit terminal 19 & Control circuit terminal 9 @ Component harness
  8. Perform the scan tool control function: Transmission Control Solenoid Valve 1 - 6, 9 - On and Off

    Verify the test lamp turns On and changes brightness.

    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Test for less than 2 ohms between the test points:
      • { P0960, P0962, P0963 } Control circuit terminal 14 @ Component harness & The other end of the circuit
      • { P0964, P0966, P0967 } Control circuit terminal 15 @ Component harness & The other end of the circuit
      • { P0968, P0970, P0971 } Control circuit terminal 16 @ Component harness & The other end of the circuit
      • { P2718, P2720, P2721 } Control circuit terminal 21 @ Component harness & The other end of the circuit
      • { P2727, P2729, P2730 } Control circuit terminal 22 @ Component harness & The other end of the circuit
      • { P2736, P2738, P2739 } Control circuit terminal 23 @ Component harness & The other end of the circuit
      • { P2824, P2826, P2827 } Control circuit terminal 19 @ Component harness & The other end of the circuit
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • Go to next step: If less than 2 ohms
    4. Ignition - On / Vehicle - In Service Mode
    5. Test for less than 1 V between the test points:
      • { P0960, P0962, P0963 } Control circuit terminal 14 @ Component harness & Ground
      • { P0964, P0966, P0967 } Control circuit terminal 15 @ Component harness & Ground
      • { P0968, P0970, P0971 } Control circuit terminal 16 @ Component harness & Ground
      • { P2718, P2720, P2721 } Control circuit terminal 21 @ Component harness & Ground
      • { P2727, P2729, P2730 } Control circuit terminal 22 @ Component harness & Ground
      • { P2736, P2738, P2739 } Control circuit terminal 23 @ Component harness & Ground
      • { P2824, P2826, P2827 } Control circuit terminal 19 @ 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
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Test for infinite resistance between the test points:
      • { P0960, P0962, P0963 } Control circuit terminal 14 @ Component harness & Ground
      • { P0964, P0966, P0967 } Control circuit terminal 15 @ Component harness & Ground
      • { P0968, P0970, P0971 } Control circuit terminal 16 @ Component harness & Ground
      • { P2718, P2720, P2721 } Control circuit terminal 21 @ Component harness & Ground
      • { P2727, P2729, P2730 } Control circuit terminal 22 @ Component harness & Ground
      • { P2736, P2738, P2739 } Control circuit terminal 23 @ Component harness & Ground
      • { P2824, P2826, P2827 } Control circuit terminal 19 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K71 Transmission Control Module
    • Go to next step: If the test lamp turns On and changes brightness 
  9. Connect the electrical connector: X1 @ T12 Automatic Transmission
  10. Remove the component:
    • Transmission Fluid Pan
    • G5 Automatic Transmission Auxiliary Fluid Pump
  11. Disconnect the electrical connector: X176
  12. Connect a test lamp between the test points:
    • { P2670, P2671 } Control circuit terminal 18 @ Component harness & Ground
    • { P0960, P0962, P0963 } Control circuit terminal 15 & Control circuit terminal 18 @ Component harness
    • { P0964, P0966, P0967 } Control circuit terminal 16 & Control circuit terminal 18 @ Component harness
    • { P0968, P0970, P0971 } Control circuit terminal 17 & Control circuit terminal 18 @ Component harness
    • { P2718, P2720, P2721 } Control circuit terminal 20 & Control circuit terminal 18 @ Component harness
    • { P2727, P2729, P2730 } Control circuit terminal 21 & Control circuit terminal 18 @ Component harness
    • { P2736, P2738, P2739 } Control circuit terminal 22 & Control circuit terminal 18 @ Component harness
    • { P2824, P2826, P2827 } Control circuit terminal 1 & Control circuit terminal 18 @ Component harness
  13. Perform the scan tool control function:
    • { P2670, P2671 } High Side Driver 2 - On and Off
    • { P0960, P0962, P0963, P0964, P0966, P0967, P0968, P0970, P0971, P2718, P2720, P2721, P2727, P2729, P2730, P2736, P2738, P2739, P2824, P2826, P2827 } Transmission Control Solenoid Valve 1 - 6, 9 - On and Off
      • Verify the test lamp turns On and changes brightness.
    • If the test lamp is always Off 

      Replace the component: Automatic Transmission Wiring Harness - (Pass-Thru)

    • Go to next step: If the test lamp turns On and changes brightness 
  14. Remove the component: Control Valve Body
  15. Connect the electrical connector: X176
  16. Disconnect the electrical connector: X177
  17. Connect a test lamp between the test points: Control circuit terminal 7 & Control circuit terminal 4
  18. Perform the scan tool control function: Transmission Control Solenoid Valve 9 - On and Off

    Verify the test lamp turns On and changes brightness.

    • If the test lamp is always Off 

      Replace the component: Automatic Transmission Wiring Harness - (Main/Solenoid)

    • Go to next step: If the test lamp turns On and changes brightness 
  19. Connect the electrical connector: X177
  20. Verify DTC P2824, P2826, P2827 is not set.
    • If the DTC is set 
    1. Disconnect the electrical connector: Q77J Transmission Control Solenoid Valve 9
    2. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2 @ Component harness
    3. Perform the scan tool control function: Transmission Control Solenoid Valve 9 - On and Off

      Verify the test lamp turns On and changes brightness.

      • If the test lamp is always Off - Replace the component: Automatic Transmission Wiring Harness - (Jumper)
      • If the test lamp turns On and changes brightness - Test or replace the component: Q77 Transmission Control Solenoid Valve
    • Go to next step: If the DTC is not set 
  21. Disconnect the appropriate electrical connector: Q77 Transmission Control Solenoid Valve
  22. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2 @ Component harness
  23. Perform the scan tool control function: Transmission Control Solenoid Valve 1 - 6 - On and Off

    Verify the test lamp turns On and changes brightness.

    • If the test lamp is always Off 

      Replace the component: Automatic Transmission Wiring Harness - (Main-Solenoid)

    • Go to next step: If the test lamp turns On and changes brightness 
  24. Test or replace the component: Q77 Transmission Control Solenoid Valve
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