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Test Description

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 3:  This step tests the system for restrictions.
  2. 5:  This step tests the following components for the following conditions:
    • The pump for internal leaks
    • The power steering pipes for kinks
  3. 6:  This step tests the ability of the pump to regulate flow at maximum pressure.
  4. 8:  This step tests the ability of the pump to regulate flow under normal operating conditions.
  5. 10:  This step tests the internal components of the pump and the gear.
Power Steering System Test Procedure

Step Action Value(s) Yes No
NOTE: If the power steering system has been serviced, an accurate fluid level reading cannot be obtained unless air is bled from the steering system. The air in the fluid may cause pump cavitation noise and may cause pump damage over a period of time.
IMPORTANT: In order to accurately diagnose the system, the malfunction must be present during the test procedure.
DEFINITION: The Power Steering System Test Procedure will perform the following functions:
  • Test the operation of the hydraulic power steering.
  • Test the operation of the power steering pump and power steering gear.
  • Identify restrictions in the system.
1
  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 pressure pipe/hose from the power steering pump or the power steering gear as necessary.
  4. Install the J 44721  Power Steering System Analyzer between the power steering pump and the power steering gear on the pressure side. See Special Tools and Equipment . Adapters may be required.
  5. Inspect and add ONLY approved power steering fluid as necessary in order to ensure that the power steering fluid is at the proper level and not contaminated. Refer to Checking and Adding Power Steering Fluid .
Is the fluid at the proper level and free from contamination?		 - Go to Step 3  Go to Step 2 
2 Fill or drain and refill the fluid as necessary. Refer to Checking and Adding Power Steering Fluid .
Is the fluid at the proper level and free from contamination?		 - Go to Step 3  -
3 
  1. Fully open the J 44721  valve. See Special Tools and Equipment .
  2. Start the engine.
    3. NOTE: Refer to Steering Wheel in the Full Turn Position Notice in Cautions and Notices.
  3. Turn the steering wheel and BRIEFLY hold the steering wheel against the steering stop in order to release any trapped air from the system.
  4. Inspect and ensure that all of the power steering pipe/hose connections are not leaking.
  5. Observe the pressure reading.
Is the pressure reading greater than the specified value?		 1379 kPa
(230 psi)		 Go to Step 4  Go to Step 5 
4
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 16  -
5 
  1. Inspect and add ONLY approved power steering fluid as necessary in order to ensure that the power steering fluid is at the proper level. Refer to Checking and Adding Power Steering Fluid .
  2. Allow the engine to run until the engine reaches full operating temperature.
  3. Record the pressure reading and flow reading (A).
  4. Partially close the J 44721  valve until the system pressure reaches the specified value, then record the FLOW reading (B). See Special Tools and Equipment .
  5. Subtract flow reading B from flow reading A.
Is the flow DECREASE greater than 3.8 L (1 gal) per minute?		 4827 kPa
(700 psi)		 Go to Step 11  Go to Step 6 
6 
NOTE: Do not leave the valve fully closed for more than 5 seconds, or the pump could be damaged internally.
  1. Fully close then open the J 44721  valve 3 times. See Special Tools and Equipment .
  2. Record all of the high pressure readings. Refer to Power Steering Pump Specifications  for power steering system pressure relief specifications.
Are the 3 high pressure readings within specifications?		 - Go to Step 7  Go to Step 13 
7 Are the 3 high pressure readings within the specified value of each other? 245 kPa (50 psi) Go to Step 8  Go to Step 12 
8 
  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 actual flow reading within specifications?		 - Go to Step 9  Go to Step 11 
9 Is the difference between the actual flow reading and the maximum flow specification more than 3.8 L (1 gal) per minute? - Go to Step 14  Go to Step 10 
10 
NOTE: Refer to Steering Wheel in the Full Turn Position Notice in Cautions and Notices.
Turn the steering wheel from steering stop to steering stop and record the FLOW readings at each stop.Is the flow LOWER than the specified value?		 3.8 L (1 gal) per minute Go to Step 17  Go to Step 15 
11 Replace the power steering pump. Refer to Power Steering Pump Replacement (4.2L) .
Did you complete the replacement?		 - Go to Step 16  -
12
  1. Remove the power steering pump flow control valve. Refer to Power Steering Pump Flow Control Valve Replacement - Off Vehicle (CB Series) .
  2. Inspect the flow control valve.

    If any burrs or scratches are noticed on the flow control valve, replace the flow control valve. Do NOT attempt to clean the flow control valve. Refer to Power Steering Pump Flow Control Valve Replacement - Off Vehicle (CB Series) .

  3. Inspect the flow control valve bore.

    If any burrs or scratches are present in the control valve bore, replace the power steering pump. Refer to Power Steering Pump Replacement (4.2L) .

Did you complete the repair?		 - Go to Step 16  -
13 Replace the power steering pump flow control valve. Refer to Power Steering Pump Flow Control Valve Replacement - Off Vehicle (CB Series) .
Did you complete the replacement?		 - Go to Step 16  -
14
  1. Remove the power steering pump flow control valve and inspect for any wear or damage. Do NOT disassemble the flow control valve.
  2. If the flow control valve is worn damaged, replace the flow control valve. Refer to Power Steering Pump Flow Control Valve Replacement - Off Vehicle (CB Series) .
Did you complete the repair?		 - Go to Step 16  -
15 The power steering gear is leaking across the piston or bypassing the valve circuit. Replace the power steering gear. Refer to Power Steering Gear Replacement .
Did you complete the replacement?		 - Go to Step 16  -
16 Test the power steering system for the original condition.
Does the original condition still exist?		 - Go to Step 1  Go to Step 17 
17
  1. Disconnect and remove the J 44721  from the vehicle. See Special Tools and Equipment .
  2. Connect the vehicle power steering pipes/hoses.
  3. Bleed the power steering system and add fluid as necessary. Refer to Bleeding the Power Steering System .
Did you complete the repair?		 - System OK -
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