Diagnostic Table
WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
- 1.NOTE: The following table is used to guide diagnosis of the refrigerant system if operating pressures are outside normal limits.
Refer to the chart below.
High (Discharge) Pressure Low (Suction) Pressure Component - Causes High Normal to High Condenser - inadequate airflow.
Engine - overheating.Normal to High Normal Refrigerant overcharge - air in refrigerant. Normal to Low High A/C Compressor - low performance. Normal to Low Normal to High (1)
A/C suction line - partially restricted or plugged.Normal to Low Low (2)
Low refrigerant charge - leak in system.Erratic Operation or Compressor Not Running Ambient Air Temperature (AAT) sensor - poor connection.
A/C pressure transducer - poor connection.
Evaporator temperature sensor - poor connection.
Low refrigerant charge - leak in system.Additional Possible Cause Components Associated With Inadequate Compressor Operation Compressor Drive Belt - loose
Compressor Clutch - slipping
Clutch Coil Open - shorted, or loose mounting
Control Assembly Switch - dirty contacts or sticking open
Clutch Wiring Circuit - high resistance, open or blown fuse
Compressor Operation Interrupted by Engine ComputerAdditional Possible Cause Components Associated With a Damaged Compressor Incorrect Clutch Air-gap
Suction Accumulator - refrigerant oil bleed hose plugged
Refrigerant Leaks(1) Low pressure reading will be normal to high if pressure is taken at accumulator and if restriction is downstream of service access valve. (2) Low pressure reading will be low if pressure is taken near the compressor and restriction is upstream of service access valve.