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 P0741 was set, operate the vehicle greater than 72 km/h (45 mph) and use the scan tool to command the TCC ON. Observe the TCC Slip Speed parameter on the scan tool. The TCC Slip Speed should be below 175 RPM.
- If the TCC Slip Speed is greater than 175 RPM, inspect the following components and repair or replace as necessary:
  - The cooling system for plugging
    The cooling lines may be pinched. Refer to Transmission Fluid Cooler Flushing and Flow Test (J35944-A) or Transmission Fluid Cooler Flushing and Flow Test (J45096) .
  - The TCC control valve for sticking
  - The TCC regulator valve for sticking
  - The pressure regulator valve
  - The TCC PWM solenoid valve stuck and O-ring seal for leaks
    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 .
  - The TCC signal orifice in the spacer plate plugged
  - The #1 check ball missing or leaking
  - The spacer plate gaskets torn or leaking
    Refer to Control Valve Body and Spacer Plate Assemble .
  - The turbine shaft seals for leaks
    Refer to Torque Converter Assembly Removal .
  - The torque converter clutch
    Refer to Torque Converter Diagnosis .
Using the scan tool, clear the DTC. If DTC P0751 or P0756 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:
  P0751
  - The 1-2 shift solenoid mechanically stuck OFF
  - A stuck or binding 1-2 shift valve
  - Damaged seals on the shift solenoid valve
  P0756
  - The 2-3 shift solenoid mechanically stuck OFF
  - A stuck or binding 2-3 shift valve
  - Damaged seals on the shift solenoid valve