Air Conditioning (A/C) System Performance Test (LM2)
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
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- This step determines if the A/C system has at least the minimum refrigerant charge
required to operate the system without damage.
- This step measures the performance of the A/C system.
- This step is to allow for vehicle variations as well as high ambient air temperatures.
Air Conditioning (A/C) System Performance Test
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Step |
Action |
Values |
Yes |
No |
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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. |
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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 2 minutes. 4. Turn OFF the ignition. 5. Install the J-43600 ACR 2000 Air Conditioning Service Center or the GE- 48800 CoolTech A/C Recharge Machine. 6. Record the ambient air temperature and humidity. 7. Record the low and high side STATIC pressure readings. Are both the low and high side pressures within the specified value? |
Above 16°C (60°F) 345 kPa (50 psi) Above 24°C (75°F) 483 kPa (70 psi) Above 33°C (90°F) 690 kPa (100 |
Go to Step 2 |
Go to Leak Testing |
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Step |
Action |
Values |
Yes |
No |
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2 |
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 or thermometers 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 and warm to operating temperature. 8. Operate the A/C system for 5 minutes. 9. Inspect A/C components for the following conditions: Abnormal frost areas Unusual noises 10. Record the following information: The panel outlet air temperatures The low-side pressure The high-side pressure 11. 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? |
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Go to Step 5 |
Go to Step 3 |
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3 |
If the pressures and temperatures recorded do not fall within the specified ranges: 1. Continue to operate the A/C system for |
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Go to Step 5 |
Go to Step 4 |
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| Step |
Action |
Values |
Yes |
No |
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2. (RESET the J-43600 Acr2000 if using). 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? |
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| 4 |
Perform the necessary repairs. Refer to A/C Diagnostics Chart. Is the action complete? |
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Go to Step 5 |
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| 5 |
Operate the system in order to verify the test results. Did you find the same results? |
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System OK |
Go to Symptoms - HVAC Systems - Automatic |
A/C Performance Table with Aux A/C
| Ambient Air Temperatur |
Relative eHumidity |
Service Port Pressure Low Side |
High Side |
Maximum Discharge Air Temperature Left Center |
Left Rear |
| 13–18°C (55–65°F) |
0–100% |
158-227 kPa (24- 33 psi) |
957-1309 kPa (139-190 psi) |
5°C (41°F) |
9°C (48°F) |
| 19–24°C (66–75°F) |
Below 40% |
179–261 kPa (26- 38 psi) |
992-1329 kPa (144-193 psi) |
8°C (45°F) |
13°C (54°F) |
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Above 40% |
186-268 kPa (27- 39 psi) |
1088-1391 kPa (158-202 psi) |
8°C (46°F) |
13°C (54°F) |
| 25–29°C (76–85°F) |
Below 35% |
220-289 kPa (32- 42 psi) |
1212-1460 kPa (176-212 psi) |
9°C (48°F) |
14°C (57°F) |
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35–50% |
220-296 kPa (32- 43 psi) |
1240-1460 kPa (180-212 psi) |
10°C 50°F) |
15°C (59°F) |
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Above 50% |
227-303 kPa (33- 44 psi) |
1260-1467 kPa (183-213 psi) |
10°C 50°F) |
15°C (59°F) |
| Ambient Air Temperatur |
Relative eHumidity |
Service Port Pressure |
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Maximum Discharge Air Temperature |
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Low Side |
High Side |
Left Center |
Left Rear |
| 30–35°C (86–95°F) |
Below 30% |
248-330 kPa (36- 48 psi) |
1371-1632 kPa (199-237 psi) |
13°C (54°F) |
18°C (63°F) |
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30–50% |
248-330 kPa (36- 48 psi) |
1378-1598 kPa (200-232 psi) |
13°C (55°F) |
18°C (64°F) |
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Above 50% |
254-337 kPa (37- 49 psi) |
1378-1557 kPa (200–226 psi) |
14°C (57°F) |
18°C (64°F) |
| 36–41°C (96–105°F) |
Below 20% |
289-365 kPa (42- 53 psi) |
1577-1839 kPa (229-267 psi) |
15°C (59°F) |
20°C (68°F) |
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20–40% |
289-365 kPa (42- 53 psi) |
1570-1770 kPa (228-257 psi) |
15°C (59°F) |
22°C (70°F) |
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Above 40% |
289-365 kPa (42- 53 psi) |
1543-1708 kPa (224-248 psi) |
17°C (61°F) |
22°C (70°F) |
| 42–46°C (106– 115°F) |
Below 20% |
323-392 kPa (47- 57 psi) |
1791-1998 kPa (260-290 psi) |
18°C (63°F) |
23°C (73°F) |
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Above 20% |
323-392 kPa (47- 57 psi) |
1756-1901 kPa (255-276 psi) |
18°C (64°F) |
23°C (73°F) |
| 47–49°C (116– 120°F) |
Below 30% |
358-427 kPa (52- 62 psi) |
1922-2101 kPa (279-305 psi) |
20°C (68°F) |
25°C (77°F) |