F48

Codes F46, F47 And/Or F48, Refrigerant System Problem






In the process of controlling the compressor clutch, the BCM monitors certain system inputs for an indication of low refrigerant charge. If the system refrigerant state of charge should fall below approximately one third of its capacity, the BCM is capable of detecting this condition and will illuminate the "Service Air Cond" telltale to warn the operator. In addition to illuminating the telltale the BCM will store a diagnostic code in memory. Codes F46, F47 and F48 all indicate that a low refrigerant condition was detected.

If the "low pressure" status indicator appears upon entering diagnostics, this indicates either a complete loss of refrigerant or malfunction in the A/C low pressure switch circuit. This chart is designed to isolate the loss of a ground signal which is normally provided to the BCM through the pressure switch contacts. These contacts open below approximately 10 psi.

If the "low pressure" status indicator does not appear, then some refrigerant remains in the system. The "ECC System Check" is designed to isolate the problems with the refrigerant system.