GM Service Manual Online
For 1990-2009 cars only

Test Description

DEFINITION: The Power Steering System Testing Procedure will perform the following functions:

    • Test the operation of the hydraulic power steering system.
    • Test the operation of the power steering pump and power steering gear.
    • Identify restrictions in the system.

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the system for restrictions.

  2. This step tests the following components for the following conditions:

  3. • The pump for internal leakage
    • The power steering pipes for restrictions
  4. This step tests the ability of the pump to regulate flow at minimum pressure.

  5. This step tests the ability of the pump to regulate flow under normal operating conditions.

  6. This step tests the internal components of the pump and the gear.

Test Procedure

Step

Action

Value(s)

Yes

No

1

Inspect the power steering fluid for the following indications of contamination:

    • Milky fluid - water
    • Brown fluid - burnt
    • Debris in fluid - plastic or dirt

Is the fluid contaminated?

--

Go to Step 2

Go to Step 3

2

Flush the power steering system. Refer to Power Steering System Flushing.

Did you complete the procedure?

--

Go to Step 3

--

3

Important: In order to accurately diagnose the system, the condition must be present during the test procedure.

Attempt to duplicate the condition.

Is the condition present?

--

Go to Step 4

System OK

4

  1. Turn the ignition switch to the OFF position.
  2. Place a drain pan under the vehicle in order to catch any power steering fluid.
  3. Disconnect the power steering gear inlet pipe/hose from the power steering pump.
  4. Install the J 44721 Power Steering System Analyser
  5. Fill the power steering system to the correct level. Refer to Checking and Adding Power Steering Fluid.
  6. Fully open the J 44721 valve.
  7. Start the engine.
  8. Notice: Refer to Steering Wheel in the Full Turn Position Notice in the Preface section.

  9. Turn the steering wheel from lock to lock three times, BRIEFLY holding the steering wheel against the steering stop each time in order to release any trapped air from the system.
  10. Inspect and make sure that all of the power steering pipe/hose connections are not leaking.

Did you complete the installation?

--

Go to Step 5

--

5

  1. Start the engine.
  2. Important: The steering must not be against the steering stop.

  3. Observe the pressure reading.

Is the pressure reading greater than the specified value?

1379  kPa

(200  psi)

Go to Step 6

Go to Step 7

6

Important: A restriction may be present in the power steering system. Turn off the engine immediately.

Locate and repair the restriction.

Did you complete the repair?

--

Go to Step 15

--

7

  1. Allow the engine to run until the engine reaches normal operating temperature.
  2. Record the pressure and flow readings.
  3. Partially close the J 44721 valve to adjust the system pressure to the specified value. Record the flow reading.
  4. Subtract second flow reading from the first flow reading.

Is the decrease in flow greater than 3.8  L (1  gal) per minute?

4827  kPa

(700  psi)

Go to Step 11

Go to Step 8

8

Important: Do not leave the valve closed for more than 5 seconds, or internal pump damage could occur.

Fully close then open the J 44721 valve 3  times. Record all of the high pressure readings. Refer to Power Steering Pump Specifications, for power steering system pressure relief specifications.

Are the three high pressure readings within specifications?

--

Go to Step 9

Go to Step 13

9

Are the three high pressure readings within 245 kPa (50 psi) of each other?

--

Go to Step 10

Go to Step 13

10

  1. Increase the engine speed to approximately 1500 RPM.
  2. Record the flow reading. Refer to Power Steering Pump Specifications, for power steering system pressure specifications.

Is the flow reading within specifications?

--

Go to Step 11

Go to Step 13

11

Is the difference between the flow reading recorded in step 7.2 and the minimum flow specification more than 3.8  L (1 gal) per minute?

--

Go to Step 13

Go to Step 12

12

Notice: Refer to Steering Wheel in the Full Turn Position Notice in the Preface section.

Turn the steering wheel from steering stop to steering stop and record the flow readings at each stop.

Is the flow lower than 3.8 L (1 gal) per minute?

--

Go to Step 15

Go to Step 14

13

Replace the power steering pump. Refer to Power Steering Pump Replacement.

Did you complete the replacement?

--

Go to Step 15

--

14

The power steering gear is leaking across the piston or bypassing the valve circuit. Replace the power steering gear. Refer to Steering Gear Replacement in Power Steering System. Refer to Steering Gear Replacement in Power Steering System.

Did you complete the replacement?

--

Go to Step 15

--

15

Test the power steering system for the original condition.

Does the original condition still exist?

--

Go to Step 5

Go to Step 16

16

  1. Disconnect and remove the J 44721 from the vehicle.
  2. Connect the power steering gear inlet pipe/hose to the power steering pump.
  3. Fill the power steering system to the correct level. Refer to Checking and Adding Power Steering Fluid.

Did you complete the procedure?

--

System OK

--