Table 1: | Gray Area Diagnosis and Service |
Table 2: | Striped Area Diagnosis and Service |
The compressor is a scroll compressor that matches the air conditioning demand by changing the compressor stroke, instead of cycling the compressor clutch. A capacity control valve located in the compressor senses the low side pressure and causes the compressor to adjust to A/C cooling demands. The compressor always runs and the system does not cycle. However, the compressor may cycle if the cooling load is not reduced enough by the capacity control valve.
• | Check the proper operation of the cooling fans. |
• | Check for system voltage above 10.5 Volts. |
• | Check the A/C fuse and replace as necessary. |
• | Check the A/C blower operation and repair as necessary. |
• | Check the clutch coil electrical connection and repair as necessary. |
• | Check the drive belt and replace if damaged or missing. |
• | Check the condenser for restricted air flow and clean as necessary. |
Refer to the following tables when you are diagnosing insufficient cooling complaints.
Step | Action | Value(s) | Yes | No | ||||||
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1 | Inspect for any stored DTCs. Are any DTCs stored? | -- | Go to Step 3 | Go to Step 2 | ||||||
2 | Connect the J 39500-B . Are the pressures above 350 kPa (50 psi)? | -- | Go to Step 4 | Go to Step 8 | ||||||
3 | Correct any stored DTCs. Refer to Diagnostic Trouble Code (DTC) List . Does the complaint persist? | -- | Go to Step 1 | System OK | ||||||
4 | Inspect and correct for a blown Air Conditioner (A/C) fuse. Does the complaint persist? | -- | Go to Step 5 | System OK | ||||||
5 |
Does the A/C clutch rotate smoothly? | -- | Go to Step 6 | System OK | ||||||
6 | Inspect and correct for the following conditions:
Does the complaint persist? | -- | Go to Step 7 | |||||||
7 | Read the DCS for Bulletins and Hints. Follow the procedures indicated. Does the complaint persist? | -- | Go to Step 10 | System OK | ||||||
8 |
Did you find a leak? | -- | Go to Step 9 | Go to Step 10 | ||||||
9 |
Does the complaint persist? | -- | Go to Step 2 | System OK | ||||||
10 | Perform an A/C Performance Check using the following steps:
Does the A/C performance meet the requirement on the Performance Chart? | -- | Go to Step 11 | Go to HVAC High Side vs. Low Side Pressure Table | ||||||
11 | Was the customer complaint made due to high temperature and/or high humidity? | -- | System OK | Go to Step 12 | ||||||
12 | Perform a leak test. Refer to Leak Testing . Did you find a leak? | -- | Go to Step 13 | System OK | ||||||
13 | Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Does the complaint persist? | -- | Go to Step 10 | System OK |
Problem | Action | ||||||||
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Important: The clutch may cycle if the discharge pressure exceeds 2758 kPa (400 psi). or if system voltage drops below 10.5 Volts. | |||||||||
Improper condenser operation | Improper condenser operation may result from one of the following causes:
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High side refrigerant restriction |
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Refrigerant system overcharged (high discharge and high suction pressures) | The clutch may cycle ON/OFF and cause compressor noise. Evacuate and recharge the system with the proper amount of refrigerant. Refer to Refrigerant Recovery and Recharging . | ||||||||
Expansion tube (orifice) blocked |
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Air in system (High discharge and high suction pressures). |
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Problem | Action | ||||||
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The compressor is damaged internally. |
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The expansion tube (orifice) is missing. | Feel the liquid line after the expansion tube. If the line is warm, discharge the system and inspect for proper installation of the expansion tube. If the expansion tube or O-ring is missing, replace the expansion tube. Refer to Auxiliary Expansion (Orifice) Tube Replacement . | ||||||
The refrigerant system is undercharged. |
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The expansion tube (orifice) is blocked. |
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