Line Pressure Check

Fig 1: View Of Transmission Fluid Pressure Gage

Courtesy of GENERAL MOTORS COMPANY

Special Tools 

GE 21867  Pressure Gauge

Equivalent regional tools: Special Tools .

WARNING:

Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.

1. Install Scan Tool
2. Start the engine.
3. Inspect the transmission for the proper fluid level, refer to Transmission Fluid Level and Condition Check .
4. Use the scan tool to inspect for any active or stored diagnostic trouble codes.
5. Inspect the manual linkage at the transmission for proper function.
6. Turn the engine OFF.
NOTE:

You may need to remove or disconnect components in order to gain access to the transmission line pressure test hole plug.

7. Remove Line Pressure Test Hole Plug
8. Install GE 21867  pressure gauge (1) - Install
9. Access the Scan Tool Transmission Output Controls for the Line PC Solenoid.
10. Start the engine.
NOTE:

In order to achieve accurate line pressure readings, the following procedure should be performed at least three times.

The values displayed on the scan tool screen will not match the actual pressures indicated on the pressure gauge.

Control the Line PC Solenoid in PARK or NEUTRAL with the engine speed at approximately 1500 RPM and the TFT between 35 - 55°C (95 - 131°F). This protects the clutches from extreme high or low line pressures and ensures a consistent pump capacity.

11. Use the scan tool to increase and decrease line pressure, allowing the pressure to stabilize between increments.
12. Compare the pressure readings on the gauge with the table below.
13. If the pressure readings on the gauge are erratic, or are more than 10% greater or less than the range specified in the table below, refer to Fluid Pressure High or Low .
14. Turn the engine OFF.
15. GE 21867  pressure gauge - Remove
CAUTION:

Refer to Fastener Caution .

16. Install Line Pressure Test Hole Plug and tighten 11 N.m (97 lb in)