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A/C Diagnostics Chart

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A/C Diagnostics Chart

Low Side Gauge Reading High Side Gauge Reading Potential Causes
Low Low Low Refrigerant Charge
Restriction between Compressor and High Side port
Low/Normal Evaporator Freezing
High Restriction between the Low Side and High Side ports or Restricted TXV/Orifice Tube
Compressor Stuck at Maximum Displacement
High Low Compressor has Low Displacement or Internal Malfunction
High Malfunctioning Cooling Fans
Refrigerant Overcharge
Restriction between the Low Side Port and Compressor Inlet
Restricted Condenser Air Flow
Expansion Device Stuck Open
Air in A/C System
Normal/High Normal/High Refrigerant Contamination
PAG or POE Oil Overcharge