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Home >> Cadillac >> 2017 >> CTS V >> Repair and Diagnosis >> External Pages >> Different car >> Section 237 (Automatic Transmission - 8L45 (M5N) Or 8L90 (M5U) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0960, P0962 or P0963: Transmission Control Solenoid Valve 1 Control Circuit >> Component Testing

Component Testing

WARNING: This page is about a different car, the 2016 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform the Circuit/System Testing first.
  2. Ignition Off, connect the X175 harness connector.
  3. Remove the fluid pan from the T12 Automatic Transmission.
  4. Disconnect the harness connector at the Q77A Transmission Control Solenoid Valve 1. Refer to Transmission Solenoid Information . Ignition On.
  5. Command the high side driver 2 Off.
  6. Connect a test lamp between terminal 2 and ground.
  7. Verify the test lamp does not illuminate.
    • If the test lamp illuminates 
    1. Disconnect the X176 harness connector.
    2. Verify a test lamp does not illuminate between the ignition circuit terminal 18 and ground.
      • If the test lamp illuminates

        Replace the automatic transmission wiring harness, electrical connector passage sleeve.

      • If the test lamp does not illuminate

        Replace the transmission control wiring harness.

    • If the test lamp does not illuminate 
  8. Verify the test lamp turns On and Off when commanding the high side driver 2 On and Off with a scan tool.
    • If the test lamp is always Off 
    1. Ignition Off, disconnect the X176 harness connector.
    2. Test for infinite resistance in the ignition circuit between terminal 18 and ground.
      • If less than infinite resistance

        Replace the automatic transmission wiring harness, electrical connector passage sleeve.

    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater

        Replace the automatic transmission wiring harness, electrical connector passage sleeve.

      • If less than 2 Ω

        Replace the transmission control wiring harness.

    • If the test lamp turns On and Off 
  9. Disconnect the test lamp.
  10. Test for 1.8-2.2 V between the control circuit terminal 1 and ground.
    • If less than 1.8 V 
    1. Ignition Off, disconnect the X176 connector, ignition On.
    2. Test for 1.8-2.2 V at the control circuit terminal 21 and ground.
      • If less than 1.8 V

        Replace the automatic transmission wiring harness, electrical connector passage sleeve.

      • If between 1.8-2.2 V

        Replace the transmission control wiring harness.

    • If greater than 2.2 V 
    1. Ignition Off, disconnect the X176 connector, ignition On.
    2. Test for 1.8-2.2 V at the control circuit terminal 21 and ground.
      • If greater than 2.2 V

        Replace the automatic transmission wiring harness, electrical connector passage sleeve.

      • If between 1.8-2.2 V

        Replace the transmission control wiring harness.

    • If between 1.8-2.2 V 
  11. Test for 4.5-5.5 Ω at 20°C (68°F) between terminal 1 and terminal 2 on the Q77A Transmission Control Solenoid Valve 1.
    • If not between 4.5 - 5.5 Ω 

      Replace the Q77A Transmission Control Solenoid Valve 1.

    • If between 4.5 - 5.5 Ω 
  12. Test for infinite resistance on the Q77A Transmission Control Solenoid Valve 1, as listed below:
    • Solenoid terminal 1 and ground
    • Solenoid terminal 2 and ground
    • If not infinite resistance 

      Replace the Q77A Transmission Control Solenoid Valve 1.

    • If infinite resistance 
  13. Replace the K71 Transmission Control Module.
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