Line Pressure Check

Line Pressure Check Procedure - For 4L60-E / 4L65-E Automatic Transmission

Line Pressure Check:

^ Tools Required
- J21867 Pressure Gage

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

Important: Before performing the line pressure check, verify that the transmission Pressure Control (PC) solenoid is operating correctly.

1. Install a scan tool.
2. Start the engine.
3. Inspect the transmission for the proper fluid levels.
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.

Important: It may be necessary to remove or disconnect components in order to gain access to the transmission line pressure test port/plug.

7. Remove the pressure plug.
8. Install the J 21867.
9. Access the Scan Tool Output Control for the PC Solenoid.
10. Start the engine.

Important: In order to achieve accurate line pressure readings, the following procedure must be performed at least three times in order to gather uniform pressure readings.

11. The scan tool is only able to control the PC solenoid in PARK and NEUTRAL with engine speeds below 1500 RPM. This protects the clutches from extreme high or low line pressures.
Begin commanding PC Solenoid at 1.0 amp and lower the amperage in one-tenth increments (0.01) until maximum line pressure is achieved.
12. Allow the pressure to stabilize between increments.
13. Compare your pressure readings to the Line Pressure table. Refer to Line Pressure.
14. If the pressure readings vary greatly from the line pressure table, refer to Oil Pressure High or Low.
15. Turn the engine OFF.
16. Remove the J21867.

Notice: Refer to Fastener Notice in Service Precautions.

17. Install the pressure plug.
^ Tighten the pressure plug to 8 - 14 Nm (6 - 10 lb ft).