Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

Perform the Transmission Fluid Check .
- Correct the transmission fluid level if the fluid is not at the proper level.
Using the scan tool, clear the DTC. If DTC P0742 was set, operate the vehicle greater than 72 km/h (45 mph) with the Calc. Throttle Position between 8-90 percent and use the scan tool to command the TCC OFF. Observe the TCC Slip Speed parameter on the scan tool. The TCC Slip Speed should be greater than 60 RPM.
- If the TCC Slip Speed is less than 60 RPM, inspect the following components and repair or replace as necessary:
  P0742
  - The TCC control valve stuck in the apply position
  - The TCC PWM solenoid valve stuck, exhaust restricted, or faulty internal O-ring
  - The TCC fluid circuits leaking
    Refer to Control Valve Body Disassemble (Without Touch Activated Power) or Control Valve Body Disassemble (With Touch Activated Power) .
  - The TCC blowoff valve or spring for damage or not seating
    Refer to Case Assembly Inspection .
  - Turbine shaft seals for leaks
    Refer to Torque Converter Assembly Removal .
  - Pump shaft seal for leaks
    Refer to Oil Pump Drive Shaft Assemble .
  - Spacer plate gaskets torn or leaking
    Refer to Control Valve Body and Spacer Plate Assemble .
  - Pressure regulator valve stuck
    Refer to Control Valve Body Disassemble (Without Touch Activated Power) or Control Valve Body Disassemble (With Touch Activated Power) .
  - Abnormally high or low line pressure
    Refer to Line Pressure Check .
Using the scan tool, clear the DTC. If DTC P0752 or P0757 is set, drive the vehicle to ensure the TCM commands 1st, 2nd, 3rd, and 4th gears. The ratios should match the commanded gear for all gears. Refer to Shift Solenoid Valve State and Gear Ratio .
- If the gear ratios do not match the commanded gear, inspect the following and repair or replace as necessary:
  P0752
  - The 1-2 shift solenoid mechanically stuck ON
  - A stuck or binding 1-2 shift valve
  P0757
  - The 2-3 shift solenoid mechanically stuck ON
  - A stuck or binding 2-3 shift valve