Line Pressure Check Procedure

Tools Required 

J 21867  Pressure Gage

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

1. Install a scan tool.
   CAUTION: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.
2. Start the engine and set the parking brake.
3. Check for a stored Diagnostic Trouble Code (DTC).
4. Repair the vehicle, if necessary.
5. Check the fluid level. Refer to the Transmission Fluid Checking Procedure 
6. Check the manual linkage for proper adjustment.
   Fig 1: Installing J 21867

   Courtesy of GENERAL MOTORS CORP.
7. Turn the engine Off. Remove the oil pressure test hole plug and install the J 21867. 
8. Put the gear selector in PARK range and set the parking brake.
9. Start the engine and allow the engine to warm up at idle.
   NOTE: Total test running time should not be longer than two minutes, or else transmission damage could occur
10. Access the PC solenoid valve control test on the scan tool.
11. 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 J 21867. 
12. See Fig. 12 in SPECIFICATIONS . Compare the data to the table.
13. If pressure readings differ greatly from the table, See Fig. 12 inSPECIFICATIONS
14. Shut the engine OFF. Remove the J 21867. 
15. Apply sealant GM P/N 12345382, (Canadian P/N 1095348) to the oil pressure test hole plug.
    NOTE: Refer to FASTENER NOTICE
16. Install the oil pressure test hole plug.

    Tighten 

    Tighten the plug to 12 N.m (106 lb in).