A8 Sedan V8-3.7L (AEW) (1997)
Refrigerant: Testing and Inspection
A/C Refrigerant System (R-134A), Troubleshooting
Test Requirements
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Using VAG 1551 Scan Tool (ST), check DTC memory for any electrical, vacuum or air distribution malfunctions, See: Heating and Air
Conditioning/Testing and Inspection
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There are no shut off requirements for the compressor: Read measuring value block, display group 001, display field 1
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The triggering and function of back pressure and recirculation door is OK.
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All air ducts, seals and covers are OK.
If one of the following conditions exists, follow recommended service:
A/C Does Not Cool (Cooling Has Stopped Completely)
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Check refrigerant system pressures. See: A/C Refrigerant System (R-134A), Checking Pressures
Insufficient Cooling During All Driving Or Engine Speed (RPM)
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Check refrigerant system pressures. See: A/C Refrigerant System (R-134A), Checking Pressures
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Low pressure switch -F73- shuts compressor off
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The high pressure switch -F118 shuts compressor off
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There is no outside airflow or airflow is severely restricted (evaporator iced up).
A/C Compressor Noisy
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Tighten A/C compressor and compressor bracket mounting bolts using torque wrench.
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Check routing of A/C refrigerant hoses and lines; hoses and lines must not contact other components and must be installed without binding,
reposition or realign as necessary.
A/C Compressor Noisy Immediately After Switching A/C ON And/or When Driving Around Corners Or Braking "refrigerant
Shock"-refrigerant System Overcharged
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Discharge refrigerant system, evacuate and recharge.
With An Otherwise Properly Operating A/C System, Water Sprays Out Of Instrument Panel Vents
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Check evaporator housing drain hose for proper routing (should not be kinked).
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Check evaporator housing drain valve.
NOTES:
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Check both evaporator drain plugs for correct installation (should not be pinched or bent).
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Check both drain valves. Must not be plugged with wax, dirt or undercoating (clean if necessary).
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Valve flaps must close properly.
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Check air plenum cover (must be properly installed and not damaged).