LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2015 >> CTS Base, AWD >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Automatic Transmission - 6L45 (MYA) - Diagnostic Information And Procedures - Sedan >> Diagnostic Information and Procedures >> DTC P0634: Control Module Overtemperature >> Circuit/System Verification
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Verification

  1. Verify the transmission fluid level and condition is correct. Refer to Transmission Fluid Level and Condition Check .
    • If the transmission fluid level and condition is not correct 

      Repair as necessary.

    • If the transmission fluid level and condition is correct 
  2. Operate the vehicle until normal engine temperature is reached.
  3. Verify with a scan tool the ECT Sensor parameter is less than 125°C (257°F).
    • If less than 125°C (257°F) 
  4. Verify the scan tool Transmission Control Module Temperature is less than 142°C (287°F).
    • If greater than 142°C (287°F) 

      Inspect the transmission fluid lines for being misrouted, kinked, or damage. Repair or replace as necessary. If the transmission fluid lines are OK, replace the Q8 Control Solenoid Valve Assembly.

    • If less than 142°C (287°F) 
  5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observe from the Freeze Frame/Failure Records data.
  6. Verify the DTC does not set.
    • If the DTC sets 

      Replace the Q8 Control Solenoid Valve Assembly.

    • If the DTC does not set 
  7. All OK.
scientia non olet · About LEMON Manuals