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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 309 (Heating, Ventilation, And Air Conditioning) >> Diagnostic Information and Procedures >> Air Conditioning (A/C) System Performance Test (Short Wheel Base) >> Test Description

Test Description

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

  1. This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.

  2. This step measures the performance of the A/C system.

  3. This step is to allow for vehicle variations as well as high ambient air temperatures.

Air Conditioning (A/C) System Performance Test (Short Wheel Base)

Step Action Values Yes No
NOTE:
  • The ambient air temperature must be at least 16°C (60°F).
  • Do not induce additional air flow across the front of the vehicle during the test.
  • If you were sent here from a DTC diagnostic table, clear the DTC upon completion of this test.
  1. Park the vehicle inside or in the shade.
  2. Open the windows in order to ventilate the interior of the vehicle.
  3. If the A/C system was operating, allow the A/C system to equalize for about 2 minutes.
  4. Turn OFF the ignition.
  5. Install the J 43600 ACR 2000 Air Conditioning Service Center.
  6. Record the ambient air temperature displayed on the J 43600 .
  7. Record the low and high side STATIC pressure readings.
Are both the low and high side pressures within the specified value?
  • Greater than 16°C (60°F), 345 kPa (50 psi)
  • Greater than 24°C (75°F), 483 kPa (70 psi)
  • Greater than 33°C (90°F), 690 kPa (100 psi)
Go to Step 2  Go to Leak Testing (Non HP2) , Leak Testing (HP2) 
    NOTE:

    Record the relative humidity and the ambient air temperature at the time of the test.

  1. Close the vehicle doors and windows.
  2. Open the drivers door window 127-152 mm (5-6 in).
  3. Select the following HVAC control settings:
    • The A/C ON.
    • The coldest temperature setting
    • The maximum blower speed
    • The I/P panel outlet mode
    • All I/P panel outlets are OPEN
    • Recirculation mode
  4. Install the temperature probes to the J 43600 in the left and right center A/C air outlets.
  5. Apply the parking brake.
  6. Place the transaxle/transmission in one of the following positions:
    • PARK for Automatic
    • NEUTRAL for Manual
  7. Start the engine.
  8. Operate the A/C system for 5 minutes.
  9. Inspect A/C components for the following conditions:
    • Abnormal frost areas
    • Unusual noises
  10. NOTE:

    Press the RESET button, before using the print function of the J 43600 .

  11. Print the following information:
    • The panel outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  12. Compare the low and high side pressures and the panel output temperatures to the table below.
Does all the data recorded fall within the specified ranges of the table below?
- Go to Step 8  Go to Step 3 
If the pressures and temperatures recorded do not fall within the specified ranges:
  1. Continue to operate the A/C system for an additional 5 minutes.
  2. RESET the J 43600 and record the pressures and temperatures again.
  3. Compare the low and high side pressures and the output temperature to the table below.

Does all the data recorded fall within the specified ranges of the table below?
- Go to Step 8  Go to Step 4 
4 Do the high and low side pressures fall within the specified ranges but the panel outlet temperatures do not? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone A  Go to Step 5 
5 Is the low side pressure greater than the specified range but the high side pressure within or less than the specified range? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone B  Go to Step 6 
6 Are the low and high side pressures both greater than the specified ranges? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone C  Go to Step 7 
7 Is the high side pressure greater than the specified range, but the low side pressure is within or less than the specified range? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone D  Go to Step 8 
8 Operate the system in order to verify the test results.
Did you find the same results?
- System OK Go to Symptoms - HVAC Systems - Manual
or
Symptoms - HVAC Systems - Automatic