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Home >> Cadillac >> 2017 >> CT6 Plug-In >> Repair and Diagnosis >> Electrical >> Body Electrical >> Hybrid/EV System Controls >> Diagnostic Information and Procedures >> DTC P181C-P181F, P183A-P183F, P184A or P184B: Internal Mode Switch Circuit >> Component Testing
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Component Testing

  1. Vehicle OFF, disconnect the X175 20-way harness connector at the transmission. Additional DTCs may set.
  2. Parking brake applied, transmission in PARK.
  3. Test for less than 2 Ω between the low reference circuit terminal 52 and each signal circuit terminal listed below:
    • Signal D2 - Terminal 53
    • Signal R2 - Terminal 39
    • Signal S - Terminal 54
    • If 2 Ω or greater 
    1. Disconnect the X1 harness connector at the B15 Transmission Internal Mode Switch.
    2. Test for less than 2 Ω in the low reference circuit and the appropriate signal circuit end to end.
      • If 2 Ω or greater, replace the a/trans wiring harness.
      • If less than 2 Ω, replace the B15 Transmission Internal Mode Switch.
    • If less than 2 Ω 
  4. Test for infinite resistance between the low reference circuit terminal 52 and each signal circuit terminal listed below:
    • Signal D1 - Terminal 40
    • Signal R1 - Terminal 38
    • If less than infinite resistance 
    1. Disconnect the X1 harness connector at the B15 Transmission Internal Mode Switch.
    2. Test for infinite resistance between the low reference circuit and the signal circuit.
      • If less than infinite resistance, replace the a/trans wiring harness.
      • If infinite resistance, replace the B15 Transmission Internal Mode Switch.
    • If infinite resistance 
  5. Transmission in NEUTRAL.
  6. Test for less than 2 Ω between the low reference circuit terminal 52 and each signal circuit terminal listed below:
    • Signal D1 - Terminal 40
    • Signal R1 - Terminal 38
    • If 2 Ω or greater 
    1. Disconnect the X1 harness connector at the B15 Transmission Internal Mode Switch.
    2. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, replace the a/trans wiring harness.
      • If less than 2 Ω, replace the B15 Transmission Internal Mode Switch.
    • If less than 2 Ω 
  7. Test for infinite resistance between the low reference circuit terminal 52 and each signal circuit terminal listed below:
    • Signal D2 - Terminal 53
    • Signal R2 - Terminal 39
    • If less than infinite resistance 
    1. Disconnect the X1 harness connector at the B15 Transmission Internal Mode Switch.
    2. Test for infinite resistance between the low reference circuit and the signal circuit.
      • If less than infinite resistance, replace the a/trans wiring harness.
      • If infinite resistance, replace the B15 Transmission Internal Mode Switch.
    • If infinite resistance 
  8. Transmission in REVERSE.
  9. Test for infinite resistance between the low reference circuit terminal 52 and the signal S circuit terminal 54.
    • If less than infinite resistance 
    1. Disconnect the X1 harness connector at the B15 Transmission Internal Mode Switch.
    2. Test for infinite resistance between the low reference circuit and the signal circuit.
      • If less than infinite resistance, replace the a/trans wiring harness.
      • If infinite resistance, replace the B15 Transmission Internal Mode Switch.
    • If infinite resistance 
  10. All OK.
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