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Home >> Cadillac >> 2018 >> Escalade Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 19 (Automatic Transmission - 6L80 (MYC) Or 6L90 (MYD) - Diagnostic Information And Procedures) >> Diagnostic Information And Procedures >> DTC P0850, P0851, Or P0852: Park/Neutral Position Switch >> Circuit/System Testing

Circuit/System Testing

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NOTE:

You must perform Circuit/System Verification first.

  1. Ignition OFF, disconnect the X1 harness connector at the Q8 Control Solenoid Valve Assembly on the automatic transmission.
  2. Install the DT-47825-10  jumper harness to the X1 vehicle harness connector.
  3. Test for less than 5 Ω between the ground circuit terminal 5 at the DT-47825-10  jumper harness and ground at the transmission case.
    • If 5 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit from wire end to wire end.
    • If 2 Ω or greater, repair the open/high resistance in the circuit.
    • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 5 Ω 
  4. Ignition ON.
  5. Test for 11 - 13 V between the signal circuit terminal 3 at the DT-47825-10  jumper harness and ground at the transmission case.
    • If not between 11 - 13 V 
    1. Ignition OFF, disconnect the X1harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the Park/Neutral signal circuit terminal 3 at the DT-47825-10  jumper harness and ground at the transmission case.
      • If less than infinite resistance, repair the short to ground in the signal circuit.
      • Go to next step: If infinite resistance.
    3. Test for less than 2 Ω in the Park/Neutral signal circuit wire end to wire end.
    • If 2 Ω or greater, repair the open/high resistance in the signal circuit.
    • If less than 2 Ω, replace the K20 Engine Control Module.
    • Go to next step: If between 11 - 13 V 
  6. Ignition OFF, disconnect the DT-47825-10  jumper harness from the X1 vehicle harness connector.
  7. Connect the DT-47825-10  jumper harness to the Q8 Control Solenoid Valve Assembly harness connector at the transmission case.
  8. Remove the transmission fluid pan.
  9. Disconnect the B15 Transmission Internal Mode Switch electrical connector from the Q8 Control Solenoid Valve Assembly.
  10. Test for less than 2 Ω between the ground circuit terminal 5 and terminal A at the B15 Transmission Internal Mode Switch connector on the Q8 Control Solenoid Valve Assembly.
    • If 2 Ω or greater 

      Replace the Q8 control solenoid valve assembly.

    • Go to next step: If less than 2 Ω 
  11. Ignition OFF.
  12. Connect the DT-47825-10  jumper harness to the X1 vehicle harness connector.
  13. Ignition ON.
  14. Test for 11 - 13 V between terminal F at the B15 Transmission Internal Mode Switch connector on the Q8 Control Solenoid Valve Assembly and ground at the transmission case.
    • If not between 11 - 13 V 

      Replace the Q8 control solenoid valve assembly.

    • Go to next step: If between 11 - 13 V 
  15. Connect a 3 A fused jumper wire between terminal F at the B15 Transmission Internal Mode Switch on the Q8 Control Solenoid Valve Assembly and ground at the transmission case.
  16. Verify the scan tool Engine Control Module Park/Neutral Position Switch parameter displays Park/Neutral.
    • If Park/Neutral is not displayed 

      Replace the K20 Engine Control Module.

    • Go to next step: If Park/Neutral is displayed 
  17. Replace the B15 Transmission Internal Mode Switch.
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