A/C Performance Test

2004 Oldsmobile Bravada AWDSECTION A/C Performance Test
WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Tools Required: ACR 2000 Air Conditioning Service center (J-43600).
  1. Park the vehicle inside or in the shade. Open the windows in order to ventilate the interior of the vehicle. If the A/C system was operating, allow the A/C system to equalize for about 2 minutes. Turn ignition off. Install the ACR 2000 Air Conditioning Service center. Record the ambient air temperature displayed on the ACR 2000 Air Conditioning Service center. Record the low and high side static pressure readings. Are both the low side and high side pressures within the specified value?
    • More Than 60°F (16°C), 50 Psi (345 kPa)
    • More Than 75°F (24°C), 70 Psi (483 kPa)
    • More Than 90°F (33°C), 100 Psi (690 kPa)
    If so, go to next step. If not, check for a refrigerant leak. See LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING.
  2. NOTE: Record the relative humidity and the ambient air temperature at the time of the test.
  3. Close the vehicle doors and windows. Open the drivers door window 5-6 inches (12.7-15.2 cm). Select the following HVAC control settings:
    • The A/C Is On
    • The Maximum Blower Speed
    • The Vent Mode
    • The Coldest Temperature Setting
    • All A/C Outlets Are Open
    Install the temperature probes of the ACR 2000 Air Conditioning Service center in the left and right center A/C air outlets. Apply the parking brake. Place the transaxle/transmission in one of the following positions:
    • With Automatic Transmission, Place Vehicle In Park
    • With Manual Transmission, Place Vehicle In Neutral
    Start the engine. Operate the A/C system for 5 minutes. Inspect A/C components for the following conditions:
    • Abnormal Frost Areas
    • Unusual Noises
    Press the reset button, before using the print function of the ACR 2000 Air Conditioning Service center. Print the following information:
    • The Outlet Air Temperatures
    • The Low-Side Pressure
    • The High-Side Pressure
    Compare the low and high side pressures and the output temperatures to the tables and chart below. See A/C SYSTEM PERFORMANCE SPECIFICATIONS - WITH FRONT A/C  or A/C SYSTEM PERFORMANCE SPECIFICATIONS - WITH REAR A/C  tables and/or Fig 1. Does all the data recorded fall within the specified ranges of the tables? If so, go to step  4. If not, go to next step.
  4. If the pressures and temperatures recorded do not fall within the specified ranges, continue to operate the A/C system for an additional 5 minutes. Reset the ACR 2000 Air Conditioning Service center and record the pressures and temperatures again. Compare the low and high side pressures and the output temperature to the tables. See A/C SYSTEM PERFORMANCE SPECIFICATIONS - WITH FRONT A/C  or A/C SYSTEM PERFORMANCE SPECIFICATIONS - WITH REAR A/C  and/or Fig 1. Does all the data recorded fall within the specified ranges of the tables? If so, go to step  8. If not, go to next step.
  5. Do the high and low side pressures fall within the specified ranges, but the outlet temperatures do not? If so, see A/C PRESSURE ZONE "A" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  6. Is the low side pressure greater than the specified range, but the high side pressure within or less than the specified range? If so, see A/C PRESSURE ZONE "B" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  7. Are the low and high side pressures both greater than the specified ranges? If so, see A/C PRESSURE ZONE "C" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  8. Is the high side pressure greater than the specified range, but the low side pressure is within or less than the specified range? If so, see A/C PRESSURE ZONE "D" DIAGNOSIS  under SYSTEM TESTS. If not, go to next step.
  9. Operate the system in order to verify the test results. Did you find the same results? If so, system is okay. If not, see SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
A/C SYSTEM PERFORMANCE SPECIFICATIONS - WITH FRONT A/C

Ambient Air Temp. - °F (°C) Low-Side Pressure - psi (kg/cm2 ) High-Side Pressure - psi (kg/cm2 ) Outlet Air Temp. - °F (°C)
55-65 (13-16) (1) 25-28 (1.75-1.96) 73-122 (5.13-8.5) 43 (6)
66-75 (19-24) (2) 25-30 (1.75-2.10) 105-158 (7.3-11.1) 43 (6)
66-75 (19-24) (3) 25-34 (1.75-2.39) 107-163 (7.5-11.4) 46 (8)
76-85 (25-29) (4) 25-35 (1.75-2.46) 145-192 (10.1-13.5) 48 (9)
76-85 (25-29) (5) 25-35 (1.75-2.46) 147-193 (10.3-13.5) 48 (9)
76-85 (25-29) (6) 27-37 (1.89-2.60) 148-197 (10.4-13.8) 52 (11)
86-95 (30-35) (7) 28-41 (1.96-2.88) 179-231 (12.5-16.2) 54 (12)
86-95 (30-35) (8) 28-41 (1.96-2.88) 180-234 (12.6-16.4) 54 (12)
86-95 (30-35) (9) 30-42 (2.10-2.95) 181-238 (12.7-16.7) 55 (13)
96-105 (36-41) (10) 34-47 (2.39-3.30) 218-270 (15.3-19.0) 59 (15)
96-105 (36-41) (11) 34-47 (2.39-3.30) 219-273 (15.4-19.2) 59 (15)
96-105 (36-41) (3) 35-47 (2.46-3.30) 221-276 (15.5-19.4) 61 (16)
106-115 (42-46) (10) 41-52 (2.88-3.65) 257-303 (18.0-21.3) 64 (18)
106-115 (42-46) (12) 41-51 (2.88-3.58) 235-306 (16.5-21.5) 64 (18)
116-120 (47-49) (7) 46-55 (3.23-3.86) 292-325 (20.5-22.8) 68 (20)
(1) With relative humidity 0-100%
(2) With relative humidity below 40%
(3) With relative humidity above 40%
(4) With relative humidity below 35%
(5) With relative humidity 35-60%
(6) With relative humidity above 60%
(7) With relative humidity below 30%
(8) With relative humidity 30-50%
(9) With relative humidity above 50%
(10) With relative humidity below 20%
(11) With relative humidity 20-40%
(12) With relative humidity above 20%
A/C SYSTEM PERFORMANCE SPECIFICATIONS - WITH REAR A/C

Ambient Air Temp. - °F (°C) Low-Side Pressure - psi (kg/cm2 ) High-Side Pressure - psi (kg/cm2 ) Left Center Outlet Air Temp. - °F (°C) Rear Center Outlet Air Temp. - °F (°C)
55-65 (13-18) (1) 25-30 (1.75-2.10) 61-125 (4.28-8.78) 43 (6) 48 (9)
66-75 (19-24) (2) 25-35 (1.75-2.46) 88-157 (6.18-11.0) 46 (8) 52 (11)
66-75 (19-24) (3) 25-39 (1.75-2.74) 99-170 (6.96-11.9) 50 (10) 55 (13)
76-85 (25-29) (4) 27-41 (1.89-2.88) 136-193 (9.56-13.5) 52 (11) 57 (14)
76-85 (25-29) (5) 29-43 2.03-3.02 144-197 (10.1-13.8) 54 (12) 59 (15)
76-85 (25-29) (6) 30-45 (2.10-3.16) 148-208 (10.4-14.6) 55 (13) 61 (16)
86-95 (30-35) (7) 34-49 (2.39-3.44) 175-238 (12.3-16.7) 59 (15) 64 (18)
86-95 (30-35) (8) 35-51 (2.46-3.58) 180-244 (12.6-17.1) 61 (16) 66 (19)
86-95 (30-35) (9) 37-53 (2.60-3.72) 186-251 (13.0-17.6) 64 (18) 70 (21)
96-105 (36-41) (10) 42-57 (2.95-4.00) 221-282 (15.5-19.8) 66 (19) 70 (21)
96-105 (36-41) (11) 43-58 (3.02-4.07) 224-287 (15.7-20.1) 68 (20) 72 (22)
96-105 (36-41) (3) 44-59 (3.09-4.14) 229-294 (16.1-20.6) 70 (21) 75 (24)
106-115 (42-46) (10) 51-64 (3.58-4.49) 267-321 (18.7-22.5) 73 (23) 75 (24)
106-115 (42-46) (11) 51-65 (3.58-4.57) 270-325 (18.9-22.8) 75 (24) 79 (26)
116-120 (47-49) (7) 58-69 (4.07-4.85) 309-345 (21.7-24.2) 77 (25) 81 (27)
(1) With relative humidity 0-100%
(2) With relative humidity below 40%
(3) With relative humidity above 40%
(4) With relative humidity below 35%
(5) With relative humidity 35-50%
(6) With relative humidity above 50%
(7) With relative humidity below 30%
(8) With relative humidity 30-50%
(9) With relative humidity above 50%
(10) With relative humidity below 20%
(11) With relative humidity 20-40%
Fig 1: Identifying A/C Pressure Zone Classification
G00185049Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.