Table 1: | Insufficient Cooling Diagnosis |
Table 2: | A/C Performance Table |
The following test measures the A/C system operating efficiency by comparing:
• | The ambient air temperature at the time of the test |
• | The ambient air humidity at the time of the test |
• | The pressure at the high-pressure side of the refrigeration system |
• | The pressure at the low-pressure side of the refrigeration system |
• | The temperature of the air being discharged from the LH and RH center IP outlets into the passenger compartment |
The number(s) below refer to the step number(s) on the diagnostic table.
This step determines if there is enough refrigerant in the A/C system to operate it without damage.
This step is to determine if the A/C compressor is operating.
This step measures the performance of the A/C system.
This step is to allow for vehicle variations as well as high ambient temperatures.
Step | Action | Value(s) | Yes | No | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform a Diagnostic System Check? | -- | Go to Step 2 | Go to A Diagnostic System Check in HVAC Systems - Manual or A Diagnostic System Check in HVAC Systems - Automatic | ||||||||||||||||||||
The low and high side pressure readings should be almost equal to each other once the system has come to rest. Are both the low and high side pressures above the specified value ? | 345 kPa (50 psi) | Go to Step 3 | Go to Leak Testing | |||||||||||||||||||||
Does the compressor clutch engage ? | -- | Go to Step 4 | Go to PCM Controlled A/C Circuit Diagnosis in Engine Controls - 3.5L | |||||||||||||||||||||
Important: Record the relative humidity and the ambient temperature AT THE TIME OF THE TEST.
Does all the recorded data fall within the specified ranges of the A/C Performance table below? | -- | Go to Step 10 | Go to Step 5 | |||||||||||||||||||||
If the pressures and temperatures recorded DO NOT fall within the specified ranges, perform the following steps:
Does all the recorded data fall within the specified ranges of the A/C Performance table below? | -- | Go to Step 10 | Go to Step 6 | |||||||||||||||||||||
6 | Compare the recorded pressures to A/C System Pressure-Zone Classification . Do both the low and high side pressures fall within Zone A on the chart? | -- | Go to Cooling Insufficient, A/C System - Pressure Zone A | Go to Step 7 | ||||||||||||||||||||
7 | Do the pressures fall within Zone B? | -- | Go to Cooling Insufficient, A/C System - Pressure Zone B | Go to Step 8 | ||||||||||||||||||||
8 | Do the pressures fall within Zone C? | -- | Go to Cooling Insufficient, A/C System - Pressure Zone C | Go to Step 9 | ||||||||||||||||||||
9 | Do the pressures fall within Zone D? | -- | Go to Cooling Insufficient, A/C System - Pressure Zone D | Go to Step 10 | ||||||||||||||||||||
10 | Operate the system in order to verify the repair. Did you correct the condition? | -- | Go to Step 11 | Go to Symptoms in HVAC System - Manual or Symptoms in HVAC System - Automatic | ||||||||||||||||||||
11 |
Is the action complete? | -- | System OK | -- |
Relative Humidity | Ambient Air Temperature | Maximum Low Side Pressure | Engine Speed | Maximum Right Center Air Outlet Temperature | Maximum High Side Pressure | ||||
---|---|---|---|---|---|---|---|---|---|
% | °F | °C | PSI | kPa | RPM | °F | °C | PSI | kPa |
20 | 70 | 21 | 37 | 255 | 2000 | 46 | 8 | 225 | 1551 |
80 | 27 | 37 | 255 | 47 | 8 | 275 | 1896 | ||
90 | 32 | 37 | 255 | 53 | 12 | 325 | 2241 | ||
100 | 38 | 38 | 262 | 54 | 12 | 325 | 2241 | ||
30 | 70 | 21 | 37 | 255 | 2000 | 48 | 9 | 240 | 1655 |
80 | 27 | 37 | 255 | 50 | 10 | 285 | 1965 | ||
90 | 32 | 39 | 269 | 57 | 14 | 340 | 2344 | ||
100 | 38 | 43 | 296 | 60 | 16 | 360 | 2482 | ||
40 | 70 | 21 | 37 | 255 | 2000 | 49 | 9 | 260 | 1793 |
80 | 27 | 37 | 255 | 53 | 12 | 305 | 2103 | ||
90 | 32 | 42 | 290 | 60 | 16 | 355 | 3137 | ||
100 | 38 | 49 | 338 | 66 | 19 | 395 | 2724 | ||
50 | 70 | 21 | 37 | 255 | 2000 | 51 | 11 | 275 | 1896 |
80 | 27 | 39 | 269 | 56 | 13 | 320 | 2206 | ||
90 | 32 | 46 | 317 | 63 | 17 | 375 | 2586 | ||
100 | 38 | 55 | 379 | 72 | 22 | 430 | 2965 | ||
60 | 70 | 21 | 37 | 255 | 2000 | 53 | 12 | 290 | 2000 |
80 | 27 | 42 | 290 | 59 | 15 | 340 | 2344 | ||
90 | 32 | 49 | 338 | 66 | 19 | 390 | 2689 | ||
100 | 38 | 60 | 414 | 78 | 26 | 445 | 3068 | ||
70 | 70 | 21 | 37 | 255 | 2000 | 55 | 13 | 305 | 2103 |
80 | 27 | 45 | 310 | 62 | 17 | 355 | 2448 | ||
90 | 32 | 53 | 365 | 70 | 21 | 405 | 2792 | ||
80 | 70 | 21 | 41 | 283 | 2000 | 56 | 13 | 320 | 2206 |
80 | 27 | 48 | 331 | 65 | 18 | 370 | 2551 | ||
90 | 32 | 57 | 393 | 73 | 23 | 420 | 2896 | ||
90 | 70 | 21 | 45 | 310 | 2000 | 58 | 14 | 335 | 2310 |
80 | 27 | 52 | 359 | 68 | 20 | 385 | 2655 |