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Home >> Cadillac >> 2019 >> CTS Base, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 68 (Automatic Transmission - 8L45 (M5N) Or 8L90 (M5U) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0960, P0962-P0964, P0966-P0968, P0970, P0971, P2736, P2738, P2739, P2812, P2814, P2815, P2824, P2826, or P2827 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: X175@T12 Automatic Transmission Assembly
  3. Connect a test lamp between the test points: Control circuit terminal 19 & 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. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 19 @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 19@Component harness & The other end of the circuit
      • 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 & Remove - Test lamp
    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 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
    • Go to next step: If the test lamp turns On and Off 
  6. Connect a test lamp between the test points: Control circuit terminal 19 &
    • { P0960, P0962, P0963 } Control circuit terminal 5@Component harness
    • { P0964, P0966, P0967 } Control circuit terminal 6@Component harness
    • { P0968, P0970, P0971 } Control circuit terminal 10@Component harness
    • { P2736, P2738, P2739 } Control circuit terminal 4@Component harness
    • { P2812, P2814, P2815 } Control circuit terminal 3@Component harness
    • { P2824, P2826, P2827 } Control circuit terminal 7@Component harness
  7. Perform the appropriate scan tool control function: Transmission Control Solenoid Valve 1, 2, 3, 6, 7, 9 - On and Off

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    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 19@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
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: 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.
      • If less than 2 ohms - Replace the component: K71 Transmission Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Test for infinite resistance between the test points: 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 Off 
  8. Disconnect the appropriate component: Q77 Transmission Control Solenoid Valve
  9. Verify a test lamp turns On between the test points: Control circuit terminal 2 & Control circuit terminal 1@
    • { P0960, P0962, P0963 } Q77A Transmission Control Solenoid Valve 1(harness side)
    • { P0964, P0966, P0967 } Q77B Transmission Control Solenoid Valve 2(harness side)
    • { P0968, P0970, P0971 } Q77C Transmission Control Solenoid Valve 3(harness side)
    • { P2736, P2738, P2739 } Q77F Transmission Control Solenoid Valve 6(harness side)
    • { P2812, P2814, P2815 } Q77G Transmission Control Solenoid Valve 7(harness side)
    • { P2824, P2826, P2827 } Q77J Transmission Control Solenoid Valve 9(harness side)
    • If the test lamp is always Off 

      Replace the appropriate component: K71 Transmission Control Module

    • Go to next step: If the test lamp turns On and Off 
  10. All OK.
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