GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 5176-E Power Steering Pressure Tester
    • J 5421-02 Thermometer

The power steering system test is a method used to identify and isolate hydraulic system difficulties. Prior to performing this test, inspect the following components and make any necessary corrections:

    • The pump reservoir for the proper fluid level. Refer to Checking and Adding Power Steering Fluid .
    • The drive belt for proper tension. Refer to Drive Belt Tensioner Diagnosis in Engine Mechanical.
    • The condition of the pump drive pulley.

    Important: Perform all the tests with the engine idling at the normal operating temperature.

  1. Turn OFF the engine.
  2. Place a container under the power steering system in order to catch the power steering fluid before disconnecting the power steering hoses.

  3. Object Number: 361684  Size: SH
  4. Disconnect the pressure hose (2) at the power steering pump (1) or at the hydraulic booster. Refer to Power Steering Hoses Replacement .

  5. Object Number: 299719  Size: SH
  6. Install the J 5176-E between the pump (1) and the hydraulic booster.
  7. Ensure that the gauge is between the shutoff valve and the pump (1).

  8. Open the shutoff valve.
  9. Remove the filler cap from the pump reservoir.
  10. Check the fluid level.

  11. Fill the pump reservoir with power steering fluid to the FULL/HOT mark on the dipstick.
  12. Start the engine.
  13. While momentarily holding the steering wheel against the stop, check the connections at the J 5176-E for leaks.
  14. Bleed the power steering system. Refer to Power Steering System Bleeding .
  15. Insert the J 5421-02 in the reservoir filler opening.
  16. Important: Do not turn the steering wheel more than five times without rolling the vehicle in order to change the tire-to-floor contact area. Failure to follow this precaution may result in flat spots on the tires.

  17. Move the steering wheel from stop to stop several times until the J 5421-02 indicates that the hydraulic fluid in the reservoir has reached a temperature of 65-77°C (150-170°F).
  18. Check the power steering pump fluid level. Add power steering fluid, if necessary.
  19. Read the J 5176-E .
  20. • The initial pressure reading on the J 5176-E , with the shutoff valve open, should not exceed 1034 kPa (150 psi).
    • Readings exceeding 1034 kPa (150 psi) indicate a restriction in the system.
    • If the reading is high, turn OFF the engine immediately. Locate and repair the restriction.

    Notice: Do not leave the valve fully closed for more than 5 seconds, or the pump could be damaged internally.

  21. Open and close the J 5176-E gauge valve fully 3 times.
  22. Record the highest pressures attained each time:
  23. • If the highest pressures are within the range of 9308-9998 kPa (1350-1450 psi) and within 345 kPa (50 psi) of each other, the system is functioning normally.
    • If the pressures recorded are within the range of 9308-9998 kPa (1350-1450 psi), but not within 345 kPa (50 psi) of each other, perform the following procedure:
         1. Remove and clean the power steering pump flow control valve.
         2. Remove any burrs using crocus cloth or a fine hone.
         3. Flush the system if it is contaminated.

    If the power steering system is exceptionally dirty, completely disassemble, clean, flush, and reassemble the pump and the gear prior to further use. Also flush the reservoir.

    • If the 3 pressure readings are within 345 kPa (50 psi) of each other, but are not within 9308-9998 kPa (1350-1450 psi), perform the following procedure:
         1. Replace the flow control valve and recheck the pressure.
         2. If the system fails the test a second time, replace the rotating group and recheck the system.
    • If the pressures are within specifications, perform the following procedure:
         1. Ensure that the valve is open.
         2. Turn the steering wheel to both stops.
         3. Record the highest pressures and compare with the maximum pump pressure recorded.
         4. If the maximum pump pressure cannot be reached in at least one side of the gear, the gear is leaking internally.
         5. Disassemble and repair the gear.
  24. Turn the engine OFF.
  25. Remove the J 5176-E .
  26. Reconnect the pressure hose (4). Refer to Power Steering Hoses Replacement .
  27. Bleed the system. Refer to Power Steering System Bleeding .
  28. Check the fluid level and/or make the necessary repairs. Refer to Checking and Adding Power Steering Fluid .
  29. Examine the steering and the front suspension thoroughly if the problem still exists. Refer to Steering Linkage Inspection in Steering Linkage and Suspension General Diagnosis in Suspension General Diagnosis.