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Home >> GMC >> 2024 >> Sierra 2500 HD Denali Ultimate >> 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 power steering system for restrictions.

  2. 7 

    This step tests the following components for the following conditions:

    • The power steering pump for internal leaks
      • NOTE:

      Power steering hoses may not look kinked, but have a layer separation causing the inner hose to collapse and restrict power steering fluid flow.

    • The power steering pipes and hoses 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 power steering system.
  • Test the operation of the power steering pump and the steering gear.
  • Identify restrictions in the power steering system.
1 Inspect the power steering fluid for the following indications of contamination:
  • Milky fluid - water
  • Brown fluid - burnt
  • Plastic debris or dirt chunks

Is the fluid free of contamination?		 - Go to Step 3  Go to Step 2 
2 Flush the power steering system. 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.
  4. Install the J-44721  Power Steering Analyzer.
  5. Fill the power steering system. Checking and Adding Power Steering Fluid 
Did you complete the installation?		 - Go to Step 5  -
5 
  1. Fully open the J-44721  Power Steering Analyzer valve.
  2. Start the engine.
    3. CAUTION:

    Refer to Steering Wheel in the Full Turn Position Caution .

  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. Make sure the steering wheel is off of the steering stop, observe the pressure reading.
Is the pressure reading greater than the specified value?		 1525 kPa
(221 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 18  -
7 
  1. Allow the engine to run until the engine reaches full operating temperature.
  2. Record the pressure reading and the flow reading.
  3. Partially close the J-44721  Power Steering 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 13  Go to Step 8 
8 
CAUTION:

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  Power Steering Analyzer valve 3 times.
  2. Record all of the high pressure readings.
  3. For power steering system pressure relief specifications, refer to Power Steering Pump Specifications .
Are the 3 high pressure readings within specifications?		 - Go to Step 9  Go to Step 15 
9 Are the three high pressure readings within 245 kPa (36 PSI) of each other? - Go to Step 10  Go to Step 14 
10 
  1. Increase the engine speed to approximately 1, 500 RPM.
  2. Record the flow reading.
  3. For power steering system pressure relief specifications, refer to Power Steering Pump 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 16  Go to Step 12 
12 
CAUTION:

Refer to Steering Wheel in the Full Turn Position Caution .

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 18  Go to Step 17 
13 Replace the power steering pump. Power Steering Pump Replacement (L5P - KHF) , or Power Steering Pump Replacement (L5P & KHF) , or Power Steering Pump Replacement (L8T - KHF) , or Power Steering Pump Replacement (L8T & KHF) 
Did you complete the replacement?		 - Go to Step 18  -
14 Replace the power steering pump. Power Steering Pump Replacement (L5P - KHF) , or Power Steering Pump Replacement (L5P & KHF) , or Power Steering Pump Replacement (L8T - KHF) , or Power Steering Pump Replacement (L8T & KHF) 
Did you complete the replacement?		 - Go to Step 18  -
15 Replace the power steering pump. Power Steering Pump Replacement (L5P - KHF) , or Power Steering Pump Replacement (L5P & KHF) , or Power Steering Pump Replacement (L8T - KHF) , or Power Steering Pump Replacement (L8T & KHF) 
Did you complete the replacement?		 - Go to Step 18  -
16 Replace the power steering pump. Power Steering Pump Replacement (L5P - KHF) , or Power Steering Pump Replacement (L5P & KHF) , or Power Steering Pump Replacement (L8T - KHF) , or Power Steering Pump Replacement (L8T & KHF) 
Did you complete the replacement?		 - Go to Step 18  -
17 The power steering gear is leaking across the piston or bypassing the valve circuit. Replace the steering gear. Hydraulic Recirculating Ball Steering Gear Replacement (SRW & NV8 - ULV) , or Hydraulic Recirculating Ball Steering Gear Replacement (DZW & NV8) , or Hydraulic Recirculating Ball Steering Gear Replacement (DZW - NV8) , or Hydraulic Recirculating Ball Steering Gear Replacement (SRW - NV8) , or Hydraulic Recirculating Ball Steering Gear Replacement (SRW & NV8 & ULV) 
Did you complete the replacement?		 - Go to Step 18  -
18 Test the power steering system for the original condition.
Does the original condition still exist?		 - Go to Step 5  Go to Step 19 
19
  1. Remove the J-44721  Power Steering Analyzer from the vehicle.
  2. Connect the vehicle power steering pipes/hoses.
  3. Bleed the power steering system. Power Steering System Bleeding 
Did you complete the repair?		 - System OK -
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