Hummer H2. Manual - part 2111

DIAGNOSTIC INFORMATION AND PROCEDURES

DIAGNOSTIC STARTING POINT - POWER STEERING SYSTEM 

Begin the system diagnosis by reviewing the system Description and Operation. Reviewing the Description and 
Operation information will help you determine the correct symptom diagnostic procedure when a malfunction 
exists. Reviewing the Description and Operation information will also help you determine if the condition 
described by the customer is normal operation. Refer to Symptoms - Power Steering System in order to 
identify the correct procedure for diagnosing the system and where the procedure is located. 

SYMPTOMS - POWER STEERING SYSTEM 

Visual/Physical Inspection 

z

Inspect for aftermarket devices which could affect the operation of the power steering system.  

z

Inspect the easily accessible or visible system components for obvious damage or conditions which could 
cause the symptom.  

z

Inspect the power steering reservoir for the proper power steering fluid level and condition.  

Symptoms List 

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: 

z

Power Steering Fluid Leaks  

z

Rattle, Clunk, or Shudder Noise from the Power Steering System  

z

Whine or Growl Noise from the Power Steering System  

z

Steering Effort Hard in One or Both Directions  

z

Steering Effort Too Easy in One or Both Directions  

POWER STEERING SYSTEM TEST PROCEDURE 

IMPORTANT: Review the system description and operation in order to familiarize yourself 

with the system functions. Refer to Power Steering System Description and 
Operation .

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2

  

Fig. 3: Recirculating Ball System 
Courtesy of GENERAL MOTORS CORP. 

Callouts For Fig. 3 

Test Description 

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

Callout

Component Name

1

Power Steering Return Hose

2

Power Steering Pressure Hose

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2

  

5: This step tests the system for restrictions.  

7: This step tests the following components for the following conditions: 

z

The pump for internal leaks  

z

The power steering pipes for kinks  

8: This step tests the ability of the pump to regulate flow at maximum pressure.  

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

12: This step tests the internal components of the pump and the gear.  

Power Steering System Test Procedure 

Step

Action

Value

(s)

Yes

No

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

z

Test the operation of the hydraulic power steering system.  

z

Test the operation of the power steering pump and power steering gear.  

z

Identify restrictions in the system.  

1

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

z

Milky fluid - water  

z

Brown fluid - burnt  

z

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 Flushing the Power Steering 
System . 
Did you complete the procedure?

-

Go to 

Step 3

-

3

Attempt to duplicate the condition.Is the condition present?

IMPORTANT:

In order to accurately diagnose the system, the malfunction must be 
present during the test procedure.

-

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 power steering gear as necessary.  

4. Install the J 44721 Power Steering System Analyzer. See Special 

Tools and Equipment .  

5. Fill the power steering system. Refer to Checking and Adding 

-

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2

  

Power Steering Fluid .  

Did you complete the installation?

Go to 

Step 5

-

5

1. Fully open the J 44721 valve. See Special Tools and 

Equipment .  

2. Start the engine. 

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?

NOTE:

Refer to Steering Wheel in the Full Turn Position Notice in 
Cautions and Notices.

1379 

kPa 

(230 

psi)

Go to 

Step 6

Go to 

Step 7

6

Locate and repair the restriction.Did you complete the repair?

IMPORTANT:

A restriction may be present in the power steering system. Turn off 
the engine IMMEDIATELY.

-

Go to 

Step 18

-

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 J 44721 valve until the system pressure reaches 

the specified value, then record the FLOW reading. See Special 
Tools and Equipment .  

4. Subtract 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

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. See Special Tools 
and Equipment .Are the three high pressure readings within 
specifications?

NOTE:

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

-

Go to 

Step 9

Go to 

Step 15

9

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

-

Go to 

Go to 

 

2004 Hummer H2 

2004 STEERING Power Steering System - Hummer H2