Hummer H2. Manual - part 1943

Diagnostic Aids 

For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. 

Test Description 

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

3: Tests for the proper operation of the circuit in the low voltage range.  

4: Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens 
when you perform this test, the signal circuit is shorted to ground.  

5: Tests for a short to voltage in the 5-volt reference circuit.  

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

DTC P0530 

Step

Action

Value

(s)

Yes

No

Schematic Reference: HVAC Schematics 
Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic System 
Check?

-

Go to Step 2

Go to Diagnostic 

System Check - 

HVAC Systems - 

Automatic

2

1. Turn ON the ignition with the engine OFF.  

2. With a scan tool, observe the A/C Pressure 

Sensor parameter in the Powertrain Engine Data 
list.  

Does the scan tool indicate the A/C Pressure Sensor 
parameter is within the specified range?

0.1-

4.9 V

Go to 

Diagnostic 

Aids

Go to Step 3

3

1. Turn OFF the ignition.  

2. Disconnect the A/C refrigerant pressure sensor.  

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

4. With a scan tool, observe the A/C Pressure 

Sensor parameter.  

Does the scan tool indicate that the A/C Pressure 
Sensor parameter is less than the specified value?

0.09 V

Go to Step 4

Go to Step 10

1. Turn OFF the ignition.  

2. Connect a 3-amp fused jumper wire between the 

5-volt reference circuit of the A/C refrigerant 
pressure sensor and the signal circuit of the A/C 
refrigerant pressure sensor.  

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2

  

4

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

4. With a scan tool, observe the A/C Pressure 

Sensor parameter.  

Does the scan tool indicate that the A/C Pressure 
Sensor parameter is greater than the specified value?

4.9 V

Go to Step 8

Go to Step 5

5

1. Disconnect the fused jumper wire.  

2. Measure the voltage between the 5-volt 

reference circuit of the A/C refrigerant pressure 
sensor and the low reference circuit of the A/C 
refrigerant pressure sensor.  

Does the voltage measure less than the specified 
value?

5.1 V

Go to Step 6

Go to Step 7

6

1. Turn OFF the ignition.  

2. Disconnect the negative battery cable.  

3. Measure the resistance from the low reference 

circuit of the A/C refrigerant pressure sensor to a 
good ground.  

Does the resistance measure less than the specified 
value?

5 ohm

Go to Step 

12

Go to Step 11

7

Test the 5-volt reference circuit of the A/C refrigerant 
pressure sensor for a short to voltage. Refer to Circuit 
Testing and Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

16

Go to Step 13

8

Test the 5-volt reference circuit of the A/C refrigerant 
pressure sensor for a short to ground, a high resistance, 
or an open. Refer to Circuit Testing and Wiring 
Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

16

Go to Step 9

9

Test the signal circuit of the A/C refrigerant pressure 
sensor for a short to ground, a high resistance, or an 
open. Refer to Circuit Testing and Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

16

Go to Step 13

10

Test the signal circuit of the A/C refrigerant pressure 
sensor for a short to voltage. Refer to Circuit Testing 
and Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 

16

Go to Step 13

11

1. Disconnect the powertrain control module.  

2. Test the low reference circuit of the A/C 

refrigerant pressure sensor for a high resistance 

-

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2

  

SYMPTOMS - HVAC SYSTEMS - AUTOMATIC 

1. Perform the Diagnostic System Check - HVAC Systems - Automatic before using the Symptom Tables 

in order to verify that all of the following are true: 

z

There are no DTCs set.  

z

The control module can communicate via the serial data link.  

2. Review the system operation in order to familiarize yourself with the system functions. Refer to 

or an open. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems.  

Did you find and correct the condition?

Go to Step 

16

Go to Step 13

12

Inspect for poor connections at the harness connector 
of the A/C refrigerant pressure sensor. Refer to 
Testing for Intermittent Conditions and Poor 
Connections and Connector Repairs in Wiring 
Systems. 
Did you find and correct the condition?

-

Go to Step 

16

Go to Step 14

13

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

-

Go to Step 

16

Go to Step 15

14

Replace the A/C refrigerant pressure sensor. Refer to 
Air Conditioning (A/C) Refrigerant Pressure 
Sensor Replacement in Heating Ventilation and Air 
Conditioning. 
Did you complete the replacement?

-

Go to Step 

16

Go to Step 15

15

Replace the powertrain control module. Refer to 
Powertrain Control Module (PCM) Replacement in 
Engine Controls - 4.8L, 5.3L, 6.0L.Did you complete 
the replacement?

IMPORTANT:

Perform the programming procedure for the 
powertrain control module.

-

Go to Step 

16

-

16

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

2. Operate the vehicle within the Conditions for 

Running the DTC as specified in the supporting 
text.  

Does the DTC reset?

-

Go to Step 2

System OK

IMPORTANT: The following steps must be completed before using the symptom tables.

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2

  

z

Air Delivery Description and Operation  

z

Air Temperature Description and Operation  

Visual/Physical Inspection 

1. Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to Checking 

Aftermarket Accessories in Wiring Systems.  

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

cause the symptom.  

3. Verify the A/C compressor clutch turns freely and is not seized.  

4. Verify that the customer is using the correct key to enable personalization.  

5. The A/C compressor will not operate in cold outside air temperatures. Refer to Air Temperature 

Description and Operation .  

6. The following conditions may cause window fogging: 

z

Wet carpet or mats  

z

High humidity  

z

Interior water leak  

z

Blocked A/C evaporator drain tube  

z

Maximum passenger capacity  

z

Blocked body pressure relief valves  

7. Inspect the air distribution system for causes of reduced air flow: 

z

Obstructed or dirty passenger compartment air filter, if equipped  

z

Blocked or damaged air inlet or outlet vents  

Intermittent 

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for 
Intermittent Conditions and Poor Connections in Wiring Systems. 

Symptom List 

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

z

HVAC Compressor Clutch Does Not Engage  

z

HVAC Compressor Clutch Does Not Disengage  

z

Blower Motor Always On  

z

Blower Motor Inoperative  

z

Blower Motor Malfunction  

z

Too Hot in Vehicle  

z

Too Cold in Vehicle  

z

Air Delivery Improper  

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2