GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 DeVille 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Air Conditioning (A/C) Diagnostics - Pressure Zone A

Step

Action

Value

Yes

No

1

Were you sent here from the A/C System Performance Test?

--

Go to Step 2

Go to Air Conditioning (A/C) System Performance Test

2

Refer to the air outlet temperatures recorded.

Does the discharge air temperature between the right and left center I/P outlets differ by 2-3 degrees?

--

Go to Step 7

Go to Step 3

3

Did the customer concern mention that the A/C system output temperature is good at first, but then turns warm during extended drives?

--

Go to Step 4

Go to Step 5

4

Increase the engine speed to 2000 RPM.

During extended operation of the A/C system, does the low side pressure decrease, possibly accompanied by heavy frost on the liquid line between the expansion device and the evaporator?

--

Go to Air Conditioning (A/C) Diagnostics - Pressure Zone D

Go to Step 5

5

Refer to the low and high side pressures recorded. Inspect for the following conditions:

Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.

    • The high side pressure slightly above the specified pressure ranges but still within zone A on the A/C Pressure-Zone Classification. Refer to Air Conditioning (A/C) System Performance Test .
    • The discharge line is hot.
    • The suction line is cool.

Do the listed conditions exist?

--

Go to Step 7

Go to Step 6

6

Refer to the low and high side pressures recorded. Inspect for the following conditions:

    • The low side pressure slightly lower than the specified ranges but still within the zone A on the A/C Pressure-Zone Classification. Refer to Air Conditioning (A/C) System Performance Test .
    • The discharge line is warm-to-hot.
    • The suction line is cool-to-warm.

Do the listed conditions exist?

--

Go to Step 8

Go to Too Hot in Vehicle in HVAC Systems-Automatic.

7

The A/C system is under charged but not enough to show a difference in low or high side pressures.

  1. Test the A/C system for leaks. Refer to Leak Testing .
  2. Recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging .

Is the repair complete?

--

Go to Step 14

--

8
  1. The A/C system may be contaminated.
  2. Inspect the J 43600 ACR Air Conditioning Service Center information screen for detection of foreign gases in A/C system.

Do foreign gases exist?

--

Go to Step 9

Go to Step 10

9
  1. Evacuate the A/C system to a scavenging tank then recharge the system to specifications. Refer to Refrigerant Recovery and Recharging .
  2. Test the A/C system for leaks. Refer to Leak Testing .

Is the repair complete?

--

Go to Step 14

--

10

The A/C system may contain too much moisture or air.

  1. Evacuate and recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging .
  2. Test the A/C system for leaks. Refer to Leak Testing .
  3. Operate the A/C system and check the outlet air temperatures. Refer to Air Conditioning (A/C) System Performance Test .

Are the outlet temperatures within the specified ranges of the A/C System Performance Test?

--

Go to Step 14

Go to Step 11

11

The A/C system may contain too much refrigerant oil.

  1. Recover the refrigerant from the A/C system. Refer to Refrigerant Recovery and Recharging .
  2. Remove the accumulator. Refer to Air Conditioning Accumulator Replacement .
  3. Drain the refrigerant oil from the accumulator and measure the amount.

Is the amount of oil greater than the specified value?

148 ml (5 oz)

Go to Step 12

Go to Step 13

12
  1. Reinstall the accumulator. Refer to Air Conditioning Accumulator Replacement .
  2. Flush the A/C system. Refer to the operating manual of the J 43600 for the flushing procedure.
  3. Add the specified amount of refrigerant oil to the A/C system. Refrigerant System Capacities .
  4. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  5. Test the A/C system for leaks. Refer to Leak Testing .

Are the repairs complete?

--

Go to Step 14

--

13
  1. Add the specified amount of refrigerant oil to the A/C system. Refrigerant System Capacities .
  2. Install the accumulator. Refer to Air Conditioning Accumulator Replacement .
  3. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  4. Test the A/C system for leaks. Refer to Leak Testing .

Are the repairs complete?

--

Go to Step 14

--

14
  1. Take readings of the low and high side pressures as well as the IP outlet air temperature.
  2. Compare the outlet temperatures to those listed in the A/C System Performance. Refer to Air Conditioning (A/C) System Performance Test .

Are the high and low side pressures and outlet temperatures within specifications?

--

Go to Step 15

Go to Air Conditioning (A/C) System Performance Test

15

Operate the system in order to verify the repair.

Did you find and correct the condition?

--

System OK

Go to Symptoms - HVAC Systems - Automatic