Hummer H2. Manual - part 2213

DTCs can be cleared with scan tool. 

Diagnostic Aids 

Repair all other DTCs before DTC C0711. 

This DTC is set when: 

z

The pneumatic status of the air suspension system is out of limits.  

z

When excessive amounts of time have elapsed when inflating the air springs.  

z

When there is a air leak in the system.  

z

When vehicle speed is greater than 3 km/h (1.8 mph) and rate of height change is out of limits.  

z

When the 60 A compressor fuse is open.  

z

When the compressor relay is defective.  

z

When there is an intermittent or permanent loss of continuity between the compressor and the compressor 
supply voltage during an upwards leveling event.  

Test Description 

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

2: Test for the proper operation of the compressor and compressor relay.  

3: Tests for open circuits in the compressor battery positive voltage circuit and compressor ground circuit. 

4: Tests for voltage in the 5-volt reference circuit.  

5: Tests for a high resistance or for an open in the low reference circuit.  

10: Check for open or high resistance in the sensor ground circuit.  

14: The replacement suspension module calibration must be checked and calibrated if necessary.  

DTC C0711 

Step

Action

Values

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 ignition, with the engine ON.  

3. With a scan tool, activate compressor test in scan 

tool output controls.  

IMPORTANT:

Be sure all doors are closed and engine is running for 
this test.

-

Go to 

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2

  

Does the compressor run and rear of vehicle raise?

Diagnostic 

Aids

Go to Step 3

3

1. Turn OFF the ignition.  

2. Check for open in 60 A ECAS fuse.  

3. Check for defective air suspension relay.  

4. Check for open or poor connections in compressor 

battery positive voltage circuit.  

5. Check for open or poor connections in compressor 

ground circuit.  

Did you find and correct the condition?

-

Go to Step 

15

Go to Step 4

4

1. Turn ON the ignition.  

2. Disconnect the air suspension pressure sensor.  

3. Measure the voltage between the 5-volt reference 

circuit of the air pressure sensor and the low 
reference circuit of the air pressure sensor.  

Is the voltage less than the specified value?

5.0 V

Go to Step 5

Go to Step 6

5

1. Turn OFF the ignition.  

2. Measure the resistance from the low reference 

circuit of the air pressure sensor to a good ground. 

Is the resistance less than the specified value?

5 ohm

Go to Step 7

Go to Step 10

6

Test the 5-volt reference circuit of the air pressure sensor 
for a short to voltage. Refer to Circuit Testing and to 
Testing for a Short to Voltage in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

15

Go to Step 12

7

Test the 5-volt reference circuit of the air pressure sensor 
for one of the following conditions: 

z

A short to ground  

z

A high resistance  

z

An open  

 
Refer to Circuit Testing and to Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

15

Go to Step 12

Test the signal circuit of the air pressure sensor for one 
of the following conditions: 

z

A short to ground  

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2

  

8

z

A high resistance  

z

An open  

 
Refer to Circuit Testing and to Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

15

Go to Step 9

9

Test the signal circuit of the air pressure sensor for a 
short to voltage. Refer to Testing for a Short to 
Voltage and to Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

15

Go to Step 12

10

1. Disconnect the air suspension module.  

2. Test the low reference circuit of the air pressure 

sensor for a high resistance or for an open. Refer 
to Circuit Testing and to Wiring Repairs in 
Wiring Systems.  

Did you find and correct the condition?

-

Go to Step 

15

Go to Step 12

11

Inspect for poor connections at the harness connector of 
the air pressure sensor. 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 

15

Go to Step 13

12

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 

15

Go to Step 14

13

Replace the air suspension pressure sensor. Refer to 
Valve Automatic Level Control Solenoid 
Replacement . 
Did you complete the replacement?

-

Go to Step 

15

-

14

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 

15

-

 

2004 Hummer H2 

2004 SUSPENSION Air Suspension - Hummer H2

  

DTC C0712 

Circuit Description 

The air suspension compressor motor is switched ON and OFF via an air suspension relay which is controlled 
by the air suspension module. The air suspension module provides a switched path to voltage whenever 
compressor activity is required. The air suspension module monitors the compressor motor relay circuity to 
determine if the voltage level agrees with the command state. 

Conditions for Running the DTC 

Ignition ON 

Conditions for Setting the DTC 

Air suspension module senses relay circuity voltage does not agree with command state. 

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 when the compressor relay circuitry is shorted to ground, voltage and open. 

Test Description 

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

2: During the air suspension relay operation, listen for an audible click. Command the ON and the OFF 
states. Repeat the commands as necessary.  

3: Verifies that the air suspension module is providing voltage to the air suspension relay.  

4: Tests for an open in the ground circuit to the air suspension relay.  

5: Tests for constant voltage to the air suspension relay. 

15

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