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Home >> Buick >> 2018 >> Encore Base >> Repair and Diagnosis >> Steering >> Power Steering System >> Diagnostic Information and Procedures >> Power Steering System Test >> Test Description

Test Description

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

  1. 5 

    This step tests the system for restrictions.

  2. 7 

    This step tests the following components for the following conditions:

    • The power steering pump for internal leaks
    • The power steering pipes for kinks
  3. 8 

    This step tests the ability of the power steering pump to regulate flow at maximum pressure.

  4. 10 

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

  5. 12 

    This step tests the internal components of the power steering pump and the steering gear.

Step Action Value(s) Yes No
DEFINITION: The Power Steering System Test procedure will perform the following functions:
  • Test the operation of the hydraulic power steering system.
  • Test the operation of the power steering pump and the steering gear.
  • Identify restrictions in the system.
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 free of contamination?		 - Go to Step 3  Go to Step 2 
2 Flush the power steering system. Refer to Power Steering System Flushing .
Did you complete the procedure?		 - Go to Step 3  -
3
NOTE:

In order to accurately diagnose the system, the malfunction 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 pressure pipe/hose from the power steering pump or the steering gear as necessary.
  4. Install the CH-44721  analyzer.
  5. Fill the power steering system. Refer to Checking and Adding Power Steering Fluid .
Did you complete the installation?		 - Go to Step 5  -
5 
  1. Fully open the CH-44721  analyzer valve.
  2. Start the engine.
    3. CAUTION:

    Do not hold the steering wheel in the full turn position longer than 5 seconds, as damage to the steering pump may result.

  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. With the steering wheel OFF of the steering stop, 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
NOTE:

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 full operating temperature.
  2. Record the pressure reading and flow reading.
  3. Partially close the CH-44721  analyzer valve until the system pressure reaches the specified value, then record the FLOW reading.
  4. Subtract the second flow reading from the first flow reading.
Is the flow DECREASE greater than 3.8 L (1 gal) per minute?		 4827 kPa
(700 psi)		 Go to Step 11  Go to Step 8 
8 
NOTE:

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

Fully close then open the CH-44721  analyzer valve 3 times. Record all of the high pressure readings. Refer to Power Steering Pump Specifications  for the power steering system pressure relief specifications.Are the 3 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 1, 500 RPM.
  2. Record the flow reading. Refer to Power Steering Pump Specifications  for the power steering system high flow specifications.
Is the actual flow reading within specifications?		 - Go to Step 11  Go to Step 13 
11 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 13  Go to Step 12 
12  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 steering gear is leaking across the piston or bypassing the valve circuit. Replace the steering gear. Refer to Steering Gear Replacement (N40 With MNK) Steering Gear Replacement (NJ1 With MNH or MNK) Steering Gear Replacement (NJ1 With MR5) Steering Gear Replacement (N40 With M4P) .
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 CH-44721  analyzer from the vehicle.
  2. Connect the vehicle power steering pipes/hoses.
  3. Fill and bleed the power steering system. Refer to Power Steering System Bleeding .
Did you complete the procedure?		 - System OK -
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