Step
| Action
| Value
| Yes
| No
|
DEFINITION: The high and low side pressures may be normal or slightly less than normal.
• | Slight Refrigerant Under Charge |
• | Refrigerant Contamination |
|
1
| Were you sent here from the air conditioning (A/C) System Performance Test?
| -
| Go to Step 2
| Go to Air Conditioning (A/C) System Performance Test
|
2
| Refer to the instrument panel outlet air temperatures recorded during the A/C system performance test.
Does the discharge air temperature between the right and left centre instrument panel outlets vary by more than 1-2°C (2-3°F)?
| -
| Go to Step 7
| Go to Step 3
|
3
| Did the customer mention that the A/C system output temperatures are good at first, but then turn warm during extended drives?
| -
| Go to Step 4
| Go to Step 5
|
4
| Increase engine speed to 2,000 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 pressures recorded during the A/C system performance test.
- Inspect for the following conditions:
• | The high side pressure is slightly greater than the specified pressure ranges but still within Zone A on the A/C Pressure-Zone Classification Chart in the A/C System Performance Test. 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 pressures recorded during the A/C system performance test.
- Inspect for the following conditions:
• | The low side pressure is slightly lower than the specified pressure ranges but still within Zone A on the A/C Pressure-Zone Classification Chart in the A/C System Performance Test. 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 Air Conditioning (A/C) System Performance Test
|
7
| The A/C system may be undercharged.
- Leak test A/C system. Refer to Leak Testing .
- Recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging .
Is the action complete?
| -
| Go to Step 14
| -
|
8
| The A/C system may be contaminated.
View the information screen on J 43600 for detection of foreign gases in the A/C system.
Do foreign gases exist?
| -
| Go to Step 9
| Go to Step 10
|
9
|
- Evacuate the A/C system to a scavenging tank. Refer to Refrigerant Recovery and Recharging .
- Recharge the A/C system to specifications.
Is the action complete?
| -
| Go to Step 14
| -
|
10
| The A/C system may contain too much moisture or air.
- Evacuate and recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging .
- Operate the A/C system and inspect the instrument panel outlet air temperatures. Refer to Air Conditioning (A/C) System Performance Test .
Are the instrument panel outlet air temperatures within the specified ranges of the A/C Performance Test Table?
| -
| Go to Step 15
| Go to Step 11
|
11
| The A/C system may contain too much refrigerant oil.
Note: Operate the A/C system on low, in order to enhance oil flow to the high side of the system. - Operate the A/C system with the engine ticking over and the blower speed on low for approximately 15 minutes.
- Recover the refrigerant from the A/C system. Refer to Refrigerant Recovery and Recharging .
- Remove the refrigerant desiccant.
- Drain and measure the refrigerant oil from the refrigerant desiccant tube.
Was more than the specified amount of refrigerant oil drained from the refrigerant desiccant tube?
| 148 ml (5 oz)
| Go to Step 12
| Go to Step 13
|
12
|
- Reinstall the refrigerant desiccant.
- Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
Are the actions complete?
| -
| Go to Step 14
| -
|
13
|
- Add the specified amount of refrigerant oil to the system. Refer to Refrigerant System Specifications .
- Install the refrigerant desiccant.
- Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
Are the actions complete?
| -
| Go to Step 14
| -
|
14
|
- Record the low and high side pressures and the instrument panel outlet air temperature.
- Compare the instrument panel outlet air temperatures to those listed in the A/C System Performance Chart. Refer to Air Conditioning (A/C) System Performance Test .
Are the high and low side pressures and instrument panel outlet air 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 or Symptoms - HVAC Systems - Automatic .
|