Line Pressure Check Procedure

Line Pressure Check Procedure

^ Tools Required
- J 21867Pressure Gage

Line pressures are calibrated for two sets of gear ranges-Drive-Park-Neutral, and Reverse. This allows the transmission line pressure to be appropriate for different pressure needs in different gear ranges: Gear Range Line Pressure Range Minimum 50-55 psi, Drive, Park or Neutral Maximum late 230-250 psi Minimum line 90 psi, Reverse Maximum line 300 psi.





Before performing a line pressure check, verify that the pressure control solenoid for the transmission is receiving the correct electrical signal from the vehicle computer:

1. Hook up the scan tool.
2. Start the engine and set the parking brake.

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. Check for a P0748 malfunction code from the pressure control solenoid of the stored transmission. Check for other malfunction codes.
4. Repair the vehicle if necessary. Include the following areas:
^ Inspect the fluid level
^ Inspect the manual linkage at the transmission
^ Install the J21867.
5. Put the gear selector in Park and set the parking brake.
6. Start the engine and allow the engine to warm up at idle.
7. Select Special Functions on the scan tool.
8. Select Trans Output Controls/Pressure Control Solenoid on the scan tool.
9. Compare your data to the Drive-Park-Neutral line pressure chart below. This line pressure is valid for PC solenoid overrides with the vehicle stopped at idle and in Park-Neutral.
If your pressure readings differ greatly from the line pressure chart, Symptom Related Diagnostic Procedures