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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 62 (Automatic Transmission - 8L45 (M5N) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0815, P0816, or P0826 >> Circuit/System Testing

Circuit/System Testing

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    NOTE:
    • Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
    • It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector:
    • S2L Automatic Transmission Manual Shift Auxiliary Position Switch - Left
    • S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right
  3. Test for less than 10 ohms between the test points:
    • Ground circuit terminal 1 @ S2L Automatic Transmission Manual Shift Auxiliary Position Switch - Left (harness side) & Ground
    • Ground circuit terminal 1 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Ground
    • If 10 ohms or greater 
    1. Disconnect the ground connection: G201
    2. Test for less than 2 ohms between the test points:
      • Ground circuit terminal 1 @ S2L Automatic Transmission Manual Shift Auxiliary Position Switch - Left (harness side) & Ground terminal G201
      • Ground circuit terminal 1 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Ground terminal G201
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the scan tool parameter: Driver Shift Control Mode Switch @ K9 Body Control Module = Invalid
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: K9 Body Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal 4 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 4 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Ground circuit terminal 1 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side)
  7. Verify the scan tool parameter: Driver Shift Control Mode Switch @ K9 Body Control Module = Invalid
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire (s)
    2. Disconnect the appropriate electrical connector: K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 4 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & 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: Signal circuit terminal 4 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & 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: K9 Body Control Module
      • Go to next step: If the specified state 
  8. Remove - Jumper Wire (s)
  9. Test for less than 1 V between the test points: Signal circuit terminal 3 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Ground
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  10. Ignition/Vehicle - Off
  11. Test for infinite resistance between the test points: Signal circuit terminal 3 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Ground
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  12. Test for less than 2 ohms between the test points: Signal circuit terminal 3 @ S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right (harness side) & Signal circuit terminal 3 @ S2L Automatic Transmission Manual Shift Auxiliary Position Switch - Left (harness side)
    • If 2 ohms or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 ohms
  13. Test or replace the component:
    • S2L Automatic Transmission Manual Shift Auxiliary Position Switch - Left
    • S2R Automatic Transmission Manual Shift Auxiliary Position Switch - Right
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