Diagnostic Table
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
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 Compressor - low performance. Normal to Low Normal to High A/C suction line - partially restricted or plugged. (1) Normal to Low Low Low refrigerant - charge leak In the system.
A/C suction line - partially restricted or plugged. (2)Erratic Operation or Compressor Not Running Ambient air temperature sensor - poor connection.
A/C pressure transducer - poor connection.
Evaporator temperature sensor - poor connection.
Low refrigerant - charge leak in the system.Additional Possible Components or Causes Associated With Inadequate Compressor Operation - A/C compressor drive belt - loose
- A/C compressor clutch - slipping
- Clutch coil open - shorted, or loose mounting
- HVAC module
- Clutch wiring circuit - high resistance, open or blown fuse
- Compressor operation interrupted by PCM
Additional Possible Components or Causes Associated With a Damaged Compressor - Incorrect clutch air-gap
- Refrigerant leaks
(1) Low pressure reading will be normal to high if restriction is downstream of service access valve. (2) Low pressure reading will be low if restriction is upstream of service access valve.