Air Conditioning (A/C) System Performance Test
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.
- 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 temperatures.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
|
NOTE:
|
||||
| 1 |
|
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 |
NOTE:
Record the relative humidity and the ambient air temperature at the time of the test. |
- | Go to Step 5 | Go to Step 3 |
| 3 | If the pressures and temperatures recorded do not fall within the specified ranges:
Does all the data recorded fall within the specified ranges of the A/C Performance Table below? |
- | Go to Step 5 | Go to Step 4 |
| 4 | Perform the necessary repairs. Refer to A/C Diagnostics Chart . Is the action complete? |
- | Go to Step 5 | - |
| 5 | 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 Performance Table
| Ambient Temperature | Relative Humidity | Low Side Service Port Pressure | High Side Service Port Pressure | Maximum Left Center Discharge Air Temperature |
|---|---|---|---|---|
| 13 - 18°C (55 - 65°F) | 0 - 100% | 151 - 227 kPa (22 - 33 psi) | 1191 - 1467 kPa (173 - 213 psi) | 7°C (43°F) |
| 19 - 24°C (66 - 75°F) | Less than 40% | 151 - 213 kPa (22 - 31 psi) | 1419 - 1743 kPa (206 - 253 psi) | 5°C (41°F) |
| Greater than 40% | 158 - 241 kPa (23 - 35 psi) | 1398 - 1750 kPa (203 - 254 psi) | 8°C (46°F) | |
| 25 - 29°C (76 - 85°F) | Less than 35% | 158 - 220 kPa (23 - 32 psi) | 1646 - 1942 kPa (239 - 282 psi) | 8°C (45°F) |
| 35 - 50% | 172 - 227 kPa (25 - 33 psi) | 1646 - 1956 kPa (239 - 284 psi) | 8°C (46°F) | |
| Greater than 50% | 179 - 241 kPa (26 - 35 psi) | 1660 - 1977 kPa (241 - 287 psi) | 10°C (50°F) | |
| 30 - 35°C (86 - 95°F) | Less than 30% | 172 - 234 kPa (25 - 34 psi) | 1839 - 2177 kPa (267 - 316 psi) | 9°C (48°F) |
| 30 - 50% | 179 - 234 kPa (26 - 34 psi) | 1860 - 2218 kPa (270 - 322 psi) | 10°C (50°F) | |
| Greater than 50% | 186 - 241 kPa (27 - 35 psi) | 1880-2266 kPa (273 - 329 psi) | 13°C (54°F) | |
| 36 - 41°C (96 - 105°F) | Less than 20% | 186 - 248 kPa (27 - 36 psi) | 2067 - 2397 kPa (300 - 348 psi) | 12°C (52°F) |
| 20 - 40% | 186 - 241 kPa (27 - 35 psi) | 2080 - 2452 kPa (302 - 356 psi) | 13°C (54°F) | |
| Greater than 40% | 192 - 241 kPa (28 - 35 psi) | 2122 - 2501 kPa (308 - 363 psi) | 13°C (55°F) | |
| 42 - 46°C (106 - 115°F) | Less than 20% | 206 - 261 kPa (30 - 38 psi) | 2301 - 2597 kPa (334 - 377 psi) | 13°C (55°F) |
| Greater than 20% | 206 - 254 kPa (30 - 37 psi) | 2321 - 2659 kPa (337 - 386 psi) | 14°C (57°F) | |
| 47 - 49°C (116 - 120°F) | Below 30% | 220 - 268 kPa (32 - 39 psi) | 2521 - 2831 kPa (366 - 411 psi) | 17°C (61°F) |