GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 CTS 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Air Conditioning (A/C) System Performance Test

Air Conditioning (A/C) System Performance Test 3.6L (LY7), 2.8L (LP1)

Table 1: A/C Performance Table (LY7, LP1)

Test Description

This test measures the operating efficiency of the A/C system under the following conditions:

    • The current ambient air temperature
    • The current relative humidity
    • The high side pressure of the A/C system
    • The low side pressure of the A/C system
    • The temperature of the air being discharged into the passenger compartment

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.

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

    3.

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

Step

Action

Values

Yes

No

Important: 

   • 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 before starting this test.

1

  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 5 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 side and high side pressures above the specified value?

More than 16°C (60°F) - 345 kPa (50 psi)

More than 24°C (75°F) - 483 kPa (70 psi)

More than 33°C (90°F) - 690 kPa (100 psi)

Go to Step 2

Go to Leak Testing

2

Important: 

   • If DTC B0157 is set, the compressor clutch will not engage until it is cleared.
   • 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 5-6 inches (12.7-15.24cm).
  3. Start the engine.
  4. With a scan tool clear any DTCs stored in the HVAC module.
  5. Select the following HVAC control settings:
    6. • The A/C is ON
    • The maximum blower speed
    • The Face mode
    • The coldest temperature setting
    • Passenger setting is off
    • All A/C outlets are OPEN
  6. Install the temperature probes of the J 43600 in the left and right center A/C air outlets.
  7. Apply the parking brake.
  8. Place the transaxle/transmission in one of the following positions:
    9. • PARK, Automatic
    • NEUTRAL, Manual
  9. Operate the A/C system for 5 minutes.
  10. Inspect A/C components for the following conditions:
    11. • Abnormal frost areas
    • Unusual noises

    Important: Make sure that the compressor is engaged when taking the data.

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

  11. Print the following information:
    12. • The outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  12. Compare the low and high side pressures and the output temperatures to the A/C Performance Table.

Does all the data recorded fall within the specified ranges of the A/C Performance Table?

--

Go to Step 8

Go to Step 3

3

If the pressures and temperatures recorded do not fall within the specified ranges of the A/C Performance Table:

  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 A/C Performance Table.

Does all the data recorded fall within the specified ranges?

--

Go to Step 8

Go to Step 4

4

See the A/C system Pressure -- Zone Classification chart.

Do the high and low side pressures fall within the specified ranges, but the 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 or within the specified range, but the low side pressure is 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 - Automatic

A/C System Pressure - Zone Classification
Object Number: 1335427 Size: MF

A/C Performance Table (LY7, LP1)

Ambient Air Temperature

Relative Humidity

Service Port Pressure

Maximum Left Center Discharge Air Temperature

Low Side

High Side

13-18°C (55-65°F)

0-100%

150-208 kPa (21-30 psi)

630-1040 kPa (91-151 psi)

10°C (50°F)

19-24°C (66-75°F)

Below 40%

150-206 kPa (21-30 psi)

700-1110 kPa (101-161 psi)

10°C (50°F)

Above 40%

153-222 kPa (22-32 psi)

810-1230 kPa (117-179 psi)

11°C (52°F)

25-29°C (76-85°F)

Below 35%

155-215 kPa (22-31 psi)

960-1280 kPa (139-186 psi)

9°C (50°F)

35% to 50%

164-219 kPa (23-32 psi)

1020-1320 kPa (148-192 psi)

10°C (50°F)

Above 50%

170-226 kPa (24-33 psi)

1060-1390 kPa (153-202 psi)

12°C (54°F)

30-35°C (86-95°F)

Below 30%

170-229 kPa (24-33 psi)

1150-1490 kPa (166-216 psi)

11°C (52°F)

30% to 50%

174-229 kPa (25-33 psi)

1190-1530 kPa (172-222 psi)

12°C (54°F)

Above 50%

179-230 kPa (26-33 psi)

1240-1580 kPa (180-229 psi)

12°C (54°F)

36-41°C (96-105°F)

Below 20%

188-245 kPa (27-36 psi)

1380-1710 kPa (200-249 psi)

13°C (55°F)

20% to 40%

188-241 kPa (27-35 psi)

1400-1730 kPa (230-251 psi)

13°C (55°F)

Above 40%

186-238 kPa (27-35 psi)

1430-1750 kPa (207-254 psi)

15°C (56°F)

42-46°C (106-115°F)

Below 20%

207-259 kPa (30-38 psi)

1620-1900 kPa (235-276 psi)

15°C (56°F)

Above 20%

205-252 kPa (29-37 psi)

1630-1910 kPa (236-277 psi)

15°C (56°F)

47-49°C (116-120°F)

Below 30%

219-263 kPa (31-38 psi)

1820-2020 kPa (264-293 psi)

16°C (61°F)

Air Conditioning (A/C) System Performance Test 5.7 (LS6)

Table 1: A/C Performance Table (LS6)

Test Description

This test measures the operating efficiency of the A/C system under the following conditions:

    • The current ambient air temperature
    • The current relative humidity
    • The high side pressure of the A/C system
    • The low side pressure of the A/C system
    • The temperature of the air being discharged into the passenger compartment

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.

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

    3.

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

Step

Action

Values

Yes

No

Important: 

   • 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

  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 5 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 side and high side pressures above the specified value?

More than 16°C (60°F) - 345 kPa (50 psi)

More than 24°C (75°F) - 483 kPa (70 psi)

More than 33°C (90°F) - 690 kPa (100 psi)

Go to Step 2

Go to Leak Testing

2

    Important: 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 driver's door window 5-6 inches (12.7-15.24cm).
  3. Select the following HVAC control settings:
    4. • The A/C is ON
    • The maximum blower speed
    • The Face mode
    • The coldest temperature setting
    • Passenger setting is off
    • All A/C outlets are OPEN
  4. Install the temperature probes of 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:
    7. • PARK, Automatic
    • NEUTRAL, Manual
  7. Start the engine.
  8. Operate the A/C system for 5 minutes.
  9. Inspect A/C components for the following conditions:
    10. • Abnormal frost areas
    • Unusual noises

    Important: Make sure that the compressor is engaged when taking the data.

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

  10. Print the following information:
    11. • The outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  11. Compare the low and high side pressures and the output temperatures to the A/C Performance Table.

Does all the data recorded fall within the specified ranges of the A/C Performance Table?

--

Go to Step 8

Go to Step 3

3

If the pressures and temperatures recorded do not fall within the specified ranges of the A/C Performance Table:

  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 A/C Performance Table.

Does all the data recorded fall within the specified ranges?

--

Go to Step 8

Go to Step 4

4

See the A/C system Pressure -- Zone Classification chart.

Do the high and low side pressures fall within the specified ranges, but the 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 or within the specified range, but the low side pressure is 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 - Automatic

A/C System Pressure - Zone Classification
Object Number: 1530435 Size: MF

A/C Performance Table (LS6)

Ambient Air Temperature

Relative Humidity

Service Port Pressure

Maximum Left Center Discharge Air Temperature

Low Side

High Side

13-18°C (55-65°F)

0-100%

150-212 kPa (22-31 psi)

990-1730 kPa (144-251 psi)

8°C (46°F)

19-24°C (66-75°F)

Below 40%

150-214 kPa (22-31 psi)

890-1560 kPa (129-226 psi)

8°C (46°F)

Above 40%

152-234 kPa (22-34 psi)

1210-1840 kPa (176-267 psi)

10°C (50°F)

25-29°C (76-85°F)

Below 35%

162-231 kPa (24-34 psi)

1310-1760 kPa (190-255 psi)

10°C (50°F)

35-50%

172-235 kPa (25-34 psi)

1440-1820 kPa (209-264 psi)

10°C (50°F)

Above 50%

179-244 kPa (28-40 psi)

1550-1930 kPa (225-280 psi)

11°C (52°F)

30-35°C (86-95°F)

Below 30%

186-254 kPa (27-37 psi)

1610-2050 kPa (234-298 psi)

12°C (54°F)

30-50%

190-255 kPa (28-37 psi)

1670-2050 kPa (242-298 psi)

12°C (54°F)

Above 50%

195-256 kPa (28-37 psi)

1740-2040 kPa (253-296 psi)

13°C (55°F)

36-41°C (96-105°F)

Below 20%

214-281 kPa (31-41 psi)

1980-2400 kPa (287-348 psi)

14°C (57°F)

20-40%

214-277 kPa (31-40 psi)

1980-2320 kPa (287-337 psi)

14°C (57°F)

Above 40%

215-272 kPa (31-39 psi)

1970-2230 kPa (286-324 psi)

15°C (59°F)

42-46°C (106-115°F)

Below 20%

243-303 kPa (35-44 psi)

2360-2690 kPa (343-390 psi)

17°C (63°F)

Above 20%

241-295 kPa (35-43 psi)

2320-2540 kPa (337-369 psi)

16°C (61°F)

47-49°C (116-120°F)

Below 30%

263-311 kPa (38-45 psi)

2610-2770 kPa (379-402 psi)

18°C (64°F)