GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Tahoe - 4WD 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 System Performance Test

System Performance Test Pickup

Use this test and the accompanying chart in order to aide in the evaluation of the air conditioning (A/C) system performance. While increased engine RPM may provide extra capacity and cooler A/C discharge temperatures, the test results may not be repeatable due to other variables. The following test procedure must be followed.

  1. Park the vehicle indoors or in a shaded area.
  2. Engage the parking brake.
  3. Open the hood, the doors, and the windows in order to ventilate the interior.
  4. Vent the engine exhaust, if necessary.
  5. Install the high and the low side pressure gauges.
  6. Record the ambient temperature at the vehicle.
  7. Record the temperature and the relative humidity by using a psychrometer or by consulting the local weather bureau.
  8. Close the doors.
  9. Close all of the windows.
  10. Place the transmission in park (auto) or in neutral (manual).
  11. Start the engine.
  12. Set the mode control to the upper mode setting.
  13. Depress the A/C and the Max/Recirculation buttons.
  14. Set the blower speed to the HIGH position.
  15. Set the temperature control to the FULL COLD position.
  16. Open the A/C outlets.
  17. Install a temperature tester into the left center A/C outlet.
  18. Stabilize the engine speed to idle RPM.
  19. Start the timer.
  20. Operate the A/C system for about 5 minutes or until the left center outlet reaches the lowest temperature.
  21. Record the following data:
    22. • The left outlet air temperature
    • The high-side pressure
    • The low-side pressure
  22. Turn the ignition off.
  23. Compare the readings with the following table.
  24. Normally operating A/C systems should be within 5 degrees and 10-20 PSIG of the levels appearing in the table.

Relative Humidity

Ambient Air Temperature

Maximum Low Side Pressure

Engine Speed

Maximum Left Center Air Outlet Temperature

Maximum High Side Pressure

20%

21°C (70°F)

223 kPa (32 psi)

Idle

7°C (45°F)

1 138 kPa (165 psi)

20%

27°C (80°F)

239 kPa (35 psi)

Idle

8°C (47°F)

1 255 kPa (182 psi)

20%

32°C (90°F)

277 kPa (35 psi)

Idle

12°C (53°F)

1 469 kPa (213 psi)

20%

38°C (100°F)

330 kPa (48 psi)

Idle

16°C (60°F)

1 737 kPa (252 psi)

20%

43°C (110°F)

385 kPa (56 psi)

Idle

19°C (67°F)

2 020 kPa (293 psi)

30%

21°C (70°F)

230 kPa (33 psi)

Idle

10°C (49°F)

1 269 kPa (184 psi)

30%

27°C (80°F)

268 kPa (39 psi)

Idle

11°C (52°F)

1 400 kPa (203 psi)

30%

32°C (90°F)

323 kPa (47 psi)

Idle

15°C (59°F)

1 648 kPa (239 psi)

30%

38°C (100°F)

376 kPa (55 psi)

Idle

19°C (66°F)

1 862 kPa (270 psi)

30%

43°C (110°F)

430 kPa (62 psi)

Idle

22°C (72°F)

2 103 kPa (305 psi)

40%

21°C (70°F)

250 kPa (36 psi)

Idle

10°C (49°F)

1 269 kPa (184 psi)

40%

27°C (80°F)

293 kPa (43 psi)

Idle

12°C (54°F)

1 462 kPa (212 psi)

40%

32°C (90°F)

341 kPa (50 psi)

Idle

17°C (62°F)

1 682 kPa (244 psi)

40%

38°C (100°F)

391 kPa (57 psi)

Idle

20°C (68°F)

1 931 kPa (280 psi)

50%

21°C (70°F)

248 kPa (36 psi)

Idle

10°C (50°F)

1 241 kPa (180 psi)

50%

27°C (80°F)

296 kPa (43 psi)

Idle

13°C (56°F)

1 448 kPa (210 psi)

50%

32°C (90°F)

355 kPa (52 psi)

Idle

18°C (65°F)

1 675 kPa (243 psi)

50%

38°C (100°F)

417 kPa (61 psi)

Idle

21°C (70°F)

1 999 kPa (290 psi)

60%

21°C (70°F)

251 kPa (36 psi)

Idle

11°C (51°F)

1 227 kPa (178 psi)

60%

27°C (80°F)

300 kPa (44 psi)

Idle

14°C (57°F)

1 420 kPa (206 psi)

60%

32°C (90°F)

365 kPa (53 psi)

Idle

19°C (66°F)

1 689 kPa (245 psi)

60%

38°C (100°F)

427 kPa (62 psi)

Idle

22°C (71°F)

1 999 kPa (290 psi)

70%

21°C (70°F)

256 kPa (37 psi)

Idle

10°C (50°F)

1 234 kPa (179 psi)

70%

27°C (80°F)

299 kPa (43 psi)

Idle

14°C (57°F)

1 420 kPa (206 psi)

70%

32°C (90°F)

379 kPa (55 psi)

Idle

19°C (66°F)

1 737 kPa (252 psi)

80%

21°C (70°F)

254 kPa (37 psi)

Idle

10°C (50°F)

1 200 kPa (174 psi)

80%

27°C (80°F)

305 kPa (44 psi)

Idle

14°C (57°F)

1 407 kPa (204 psi)

80%

32°C (90°F)

387 kPa (56 psi)

Idle

19°C (67°F)

1 717 kPa (249 psi)

This is not a maximum A/C Capacity Test.

Increased engine temperatures may not provide repeatable test results.

System Performance Test Suburban/Yukon XL

Use this test and the accompanying chart in order to aide in the evaluation of the air conditioning (A/C) system performance. While increased engine RPM may provide extra capacity and cooler A/C discharge temperatures, the test results may not be repeatable due to other variables. The following test procedure must be followed.

  1. Park the vehicle indoors or in a shaded area.
  2. Engage the parking brake.
  3. Open the hood, the doors, and the windows in order to ventilate the interior.
  4. Vent the engine exhaust, if necessary.
  5. Install the high and the low side pressure gauges.
  6. Record the ambient temperature at the vehicle.
  7. Record the temperature and the relative humidity by using a psychrometer or by consulting the local weather bureau.
  8. Close the doors.
  9. Close all of the windows except the driver's window. Leave the driver's window open 5 inches.
  10. Place the transmission in park (auto) or in neutral (manual).
  11. Start the engine.
  12. Set the mode control to the upper mode setting.
  13. Depress the A/C and the Max/Recirculation buttons.
  14. Set the blower speed to the HIGH position.
  15. Set the temperature control to the FULL COLD position.
  16. Open the A/C outlets.
  17. Install a temperature tester into the left center A/C outlet.
  18. Stabilize the engine speed to idle RPM.
  19. Start the timer.
  20. Operate the A/C system for about 5 minutes or until the left center outlet reaches the lowest temperature.
  21. Record the following data:
    22. • The left outlet air temperature
    • The high-side pressure
    • The low-side pressure
  22. Turn the ignition off.
  23. Compare the readings with the following table.
  24. Normally operating A/C systems should be within 5 degrees and 10-20 PSIG of the levels appearing in the table.

% Relative Humidity

Ambient Air Temperature (°F/°C)

Maximum Low Side Pressure (psig/kpa)

Engine Speed

Maximum Front System Left Center Air Outlet Temperature (°F)

Maximum Rear System 3rd Seat Right Air Outlet Temperature (°C/°F)

Maximum High Side Pressure (psig/kpa)

10

110/43

54/372

Idle

64/18

66/19

248/1710

15

15

100/38

120/49

46/317

57/393

Idle

Idle

58/14

66/19

61/16

67/19

211/1455

281/1937

20

20

20

80/27

90/32

110/43

31/214

38/262

54/372

Idle

Idle

Idle

44/7

50/10

65/18

47/8

54/12

67/19

143/986

174/1200

250/1724

30

30

100/38

110/43

46/317

55/379

Idle

Idle

58/14

66/19

60/16

68/20

211/1455

253/1744

40

40

80/27

90/32

32/221

39/269

Idle

Idle

45/7

52/11

48/9

55/13

142/979

176/1214

45

45

80/27

100/38

26/179

48/331

Idle

Idle

38/3

60/16

42/6

62/17

116/800

214/1476

60

60

80/27

90/32

32/221

41/283

Idle

Idle

45/7

54/12

48/9

56/13

145/1000

178/1227

70

70/21

27/186

Idle

39/4

42/6

117/807

75

60/16

34/234

Idle

47/8

50/10

75/517