GM Service Manual Online
For 1990-2009 cars only

Measure the Line Pressure

Note: Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature 50-80°C (122-176°F). The line pressure test should always be carried out in pairs. One technician should observe the conditions of wheels or wheel stoppers outside the vehicle while the other is performing the test. Be careful to prevent the test hose from interfering with the exhaust pipe. This Check must be conducted after checking and adjusting engine. Perform under condition that A/C is OFF. When conducting stall test, do not continue more than 5 seconds.

  1. Warm up the ATF.
  2. Remove the test plug on the front left side of the transaxle case and connect Pressure Tester.
  3. Fully apply the parking brake and chock the 4 wheels.
  4. Connect the scan tool.
  5. Start the engine and check idling speed.
  6. Keep your left foot pressing firmly on the brake pedal and shift into D position.
  7. Measure the line pressure when the engine is idling.
  8. Depress the accelerator pedal all the way down. Quickly read the highest line pressure when engine speed reaches stall speed.
  9. In the same way, do the test in R position.