Step
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Action
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Yes
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No
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1
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Were you sent here from Symptoms or another diagnostic table?
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Go to
Step 2
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Go to
Symptoms - HVAC Systems - Automatic
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2
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1.
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A/C system noises can be generally categorized into 3 areas:
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•
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Screeching, squealing, chirping noises
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•
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Vibration/rattle noises
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3.
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Ensure that the A/C is ON.
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Is a screeching, squealing noise heard when the A/C is ON?
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Go to
Step 3
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Go to
Step 6
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3
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With the engine OFF, inspect the drive belt for excessive wear. Refer to
Drive Belt Falls Off and Excessive Wear Diagnosis
.
Is the drive belt excessively worn?
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Go to
Step 14
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Go to
Step 4
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4
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Inspect the drive belt tension. Refer to
Drive Belt Tensioner Diagnosis
.
Is the drive belt tension correct?
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Go to
Step 15
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Go to
Step 5
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5
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Inspect the drive belt for excessive oil coverage.
Is the drive belt covered with oil?
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Go to
Step 13
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Go to
Step 6
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6
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2.
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Ensure that the A/C is ON.
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Is the compressor locked up?
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Go to
Step 19
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Go to
Step 7
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7
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Using a stethoscope, listen to the A/C compressor for any abnormal noises.
Is the compressor causing an abnormal noise?
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Go to
Step 11
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Go to
Step 8
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8
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Listen to the A/C compressor components and mounting for noise concerns using a stethoscope.
Are any of these components loose, damaged or excessively worn?
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Go to
Step 16
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Go to
Step 9
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9
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3.
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Using a stethoscope, move around the entire refrigerant plumbing system, inspecting for any abnormal noises caused by component ground-out.
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Are any of the A/C components grounding out and causing a noise?
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Go to
Step 21
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Go to
Step 10
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10
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1.
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1. Idle the engine in PARK with the A/C on.
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2.
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2. Using a stethoscope, move around the entire A/C system testing for any abnormal noises caused by a component.
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Do any of the A/C components cause an abnormal noise?
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Go to
Step 17
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Go to
Step 20
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11
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Verify that the A/C system is properly charged. Refer to
Refrigerant System Specifications
.
Is the A/C system properly charged?
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Go to
Step 19
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Go to
Step 16
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12
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Recharge the A/C system to specification. Refer to
Refrigerant Recovery and Recharging (Belt Driven Compressor)
.
Is the abnormal compressor noise still present?
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Go to
Step 20
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Go to
Step 21
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13
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Repair the oil leak. Refer to the appropriate repair procedure in Engine Mechanical.
Is the repair complete?
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Go to
Step 21
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-
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14
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Replace the drive belt. Refer to
Drive Belt Replacement
.
Is the replacement complete?
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Go to
Step 21
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-
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15
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Replace the drive belt tensioner. Refer to
Drive Belt Replacement
.
Is the replacement complete?
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Go to
Step 21
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-
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16
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Repair or replace the A/C compressor mounting component.
Is the repair complete?
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Go to
Step 21
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-
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17
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Repair or replace the component which is causing the moaning concern as needed.
Is the repair complete?
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Go to
Step 21
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-
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18
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Correctly route or insulate the A/C component.
Is the repair complete?
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Go to
Step 21
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-
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19
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Replace the A/C compressor. Refer to
A/C compressor, replacement (LF1)
A/C compressor, replacement (LAU)
.
Is the replacement complete?
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Go to
Step 21
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-
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20
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The concern may be caused by an engine related component. Refer to
Vibration Analysis - Engine
.
Did you find and correct the condition?
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Go to
Step 21
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-
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21
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Operate the system in order to verify the repair.
Did you find and correct the condition?
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System OK
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Go to
Step 2
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