Hummer H2. Manual - part 2208

DTC C0563 

Circuit Description 

On the power-up self test, the calibration data stored in the electronically erasable programmable read-only 
memory (EEPROM) is copied to shadow RAM. Data checksums are generated and verified, and the data in 
shadow RAM is verified against the contents of the EEPROM. In certain situations data is written to the 
EEPROM. In these circumstanced any checksums are recalculated, and the data written to the EEPROM is read 
back and compared with the original data. 

Conditions for Running the DTC 

The ignition is on. 

Did you find and correct the condition?

10

Go to Step 6

6

Inspect for poor connections at the harness connector of the air 
suspension module. Refer to Testing for Intermittent 
Conditions and Poor Connections and to Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

Go to Step 

10

Go to Step 8

7

Inspect for poor connections at the harness connector of the 
ERH Switch. Refer to Testing for Intermittent Conditions 
and Poor Connections and to Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

Go to Step 

10

Go to Step 9

8

1. Replace the air suspension module. Refer to Module 

Assembly Electronic Suspension Control 
Replacement .  

2. Perform the trim height calibration procedure for the air 

suspension module if necessary after check trim height 
procedure.  

Did you complete the replacement?

IMPORTANT:

Always perform the check trim height procedure after air 
suspension module replacement.

Go to Step 

10

-

9

Replace the ride height switch. Refer to Electronic 
Suspension Switch Replacement . 
Did you complete the replacement?

Go to Step 

10

-

10

1. Use the scan tool in order to clear the DTCs.  

2. Operate the vehicle within the Conditions for Running 

the DTC.  

Does the DTC reset?

Go to Step 2

System OK

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2

  

Conditions for Setting the DTC 

If the EEPROM test fails then it is repeated. If the fault is still present after 5 test cycles, then a DTC is set. 

Action Taken When the DTC Sets 

z

Air Suspension functionality is suspended.  

z

SERVICE AIR SUSPENSION message is displayed.  

Conditions for Clearing the DTC 

DTC is cleared by cycling ignition. 

DTC C0563 

DTC C0569 

Circuit Description 

The Air Suspension Module monitors the trim height calibration procedure. When the calibration procedure is 
activated the vehicle exhaust down to rest on a chassis support at a predetermined height. When no further 
height change is detected, the height sensor readings are verified to be within 2.06 V and 2.88 V. If there are no 
errors then the new trim height is accepted. If the Air Suspension Module detects any errors in the trim height 
calibration procedure then the new trim height is not accepted and a DTC is set. 

Conditions for Running the DTC 

Ignition on 

Conditions for Setting the DTC 

The Air Suspension Module detects that the height sensors are not within 2.06 V and 2.88 V. 

Action Taken When the DTC Sets 

Step

Action

Yes

No

Schematic Reference:Suspension Controls Schematics

1

Did you perform the Air Suspension Diagnostic System 
Check?

Go to 

Step 2

Go to Diagnostic System 

Check - Air Suspension

2

Perform the trim height calibration procedure. Refer to 
Trim Height Calibration Procedure . 
Does the DTC reset?

Go to 

Step 3

System OK

3

Replace the electronic suspension control module. Refer to 
Module Assembly Electronic Suspension Control 
Replacement . 
Did you complete the replacement.

System 

OK

-

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2

  

The new trim height is not accepted. 

Conditions for Clearing the DTC 

The DTC will clear when the condition for setting the DTC is removed 

Diagnostic Aids 

Make sure the vehicle chassis is being supported at the proper trim height. 

Test Description 

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

3: Tests whether the condition is module, system, or condition related.  

4: Tests if the condition has been corrected or identified as specified in the supporting text.  

5: Test if the Air Suspension Sensors are within the proper range before the relearn procedure is 
activated.  

DTC C0569 

Step

Action

Yes

No

Schematic Reference: Suspension Controls Schematics

1

Did you perform the Air Suspension Diagnostic System 
Check?

Go to Step 2

Go to Diagnostic 

System Check - Air 

Suspension

2

1. Install a scan tool.  

2. Turn ON the ignition, with the engine OFF.  

3. With a scan tool, monitor the DTC Information for DTC 

C0569 in the Air Suspension Module.  

Does the scan tool indicate that DTC C0569 is current?

Go to Step 4

Go to Step 3

3

Most occurrences of this DTC are caused by not having the 
vehicle supported at the proper trim height when doing the 
trim height relearn procedure. 
Did trim height relearn procedure cause this DTC to set?

Go to 

Diagnostic 

Aids

Go to Step 4

4

1. Use the scan tool in order to clear the DTCs.  

2. Activate the trim height relearn procedure after making 

sure the vehicle is being supported at the correct trim 
height.  

Does the DTC reset?

Go to Step 5

System OK

5

If needed, inspect the Right and Left Height Sensor voltage 
reading with the scan tool to be sure that they read between 
2.06 V and 2.88 V after the Air Suspension system has 

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2

  

DTC C0626 

Circuit Description 

The air suspension sensor provides a signal voltage between 0.3-4.7 volts to the air suspension module. This 
signal voltage represents the wheel's position relative to the body. The air suspension module provides a 5-volt 
reference and a low reference to the sensor. 

Conditions for Running the DTC 

At power-up and continuous when ignition is activated. 

Conditions for Setting the DTC 

The air suspension module senses a suspension sensor voltage below 0.3 volts or above 4.7 volts. 

Action Taken When the DTC Sets 

z

Air Suspension functionality is suspended.  

z

SERVICE AIR SUSPENSION message is displayed.  

Conditions for Clearing the DTC 

The DTC will clear when the condition for setting the DTC is removed. 

Diagnostic Aids 

This DTC is set for a high or low signal to the air suspension module from the air suspension sensor - LR. 

Test Description 

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

exhausted. 
Did you find and correct the condition?

System OK

Go to Step 6

6

1. Replace the Air Suspension Module. Refer to Module 

Assembly Electronic Suspension Control 
Replacement .  

2. Check the trim height and recalibrate the Air 

Suspension Module if necessary.  

Did you complete the replacement?

IMPORTANT:

Always check the trim height and recalibrate the Air 
Suspension module if necessary.

System OK

-

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2