GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • DT 46450 Pressure Gage
    • J 36648-A Pressure Gage Adapter

    Important: Before performing a line pressure check, verify that the pressure control (PC) solenoid valve is receiving the correct electrical signal from the ECM.

  1. Install a scan tool.
  2. Caution: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.

  3. Start the engine and set the parking brake.
  4. Inspect for a stored Diagnostic Trouble Code (DTC).
  5. Repair the vehicle, if necessary.
  6. Check the fluid level. Refer to the Transmission Fluid Check.
  7. Check the manual linkage for proper adjustment.
  8. Caution: Refer to General Repair Instructions in the Preface section.

  9. Turn the engine Off. Remove the transmission pressure test plug (40) and install J 36648-A and DT 46450 .
  10. Put the gear selector in PARK range and set the parking brake.
  11. Start the engine and allow the engine to warm up at idle.
  12. Notice: Refer to General Repair Instructions in the Preface section.

  13. Access the PC solenoid valve control test on the scan tool.
  14. Increase the PC solenoid actual current from 0 to 1 amps in 0.1 amp increments. Allow the pressure to stabilize for five seconds after each pressure change. Read the corresponding line pressure on the DT 46450 .
  15. Refer to the Line Pressure specification table. Compare the data to the table.
  16. If pressure readings differ greatly from the table, refer to Fluid Pressure High or Low.
  17. Turn engine OFF. Remove the DT 46450 .
  18. Inspect the pressure test plug (40) and O-ring (66) for damage.
  19. Notice: Refer to Fastener Notice in the Preface section.

    Important: If the pressure test plug (40) and O-ring (66) are not damaged, they should be reused.

  20. Install the transmission pressure test plug (40).
  21. Tighten
    Tighten the transmission pressure test plug to 11 N·m (8 lb. ft).