BCM Code F48 - Refrigerant System Problems
In process of controlling compressor clutch, BCM monitors certain system inputs for an indication of low refrigerant charge. If system refrigerant state of charge should fall below about 1/3 of its capacity, BCM is capable of detecting this condition and will turn on SERVICE AIR COND light to warn operator. In addition to turning on light, BCM will store a diagnostic code in memory. These codes all indicate a low refrigerant condition was detected.
Upon entering diagnostics, low pressure status indicator (°F) appears if either a complete loss of refrigerant or a malfunction in A/C low pressure switch circuit exists. This chart is designed to isolate loss of ground signal, which is normally provided to BCM through pressure switch contacts. These contacts open at about less than 10 psi.
If low pressure status indicator does not appear, some refrigerant remains in system. Fault lies in air conditioning system controls.