Codes B446, B447 & B448, Refrigerant System Problem: Notes

Code B446 will set if low side temperature drops too quickly during compressor engagement. Code B447 will set if low side temperature drops much too quickly during compressor engagement or low refrigerant pressure switch opens during compressor engagement. Code B448 will set if low refrigerant pressure switch remains open longer than 3 minutes.

1. BCM input value BI08 displays voltage state of circuit at BCM.
2. Checks to see if open circuit reading is due to circuit or switch.
3. Checks to see if fault is on ignition side or BCM side of switch circuit.
4. Checks to see if fault is due to pressure switch or a low refrigerant charge.

Previous chart has determined problem is not in low refrigerant pressure switch circuit.

1. This is a test to determine if A/C low refrigerant pressure switch opens while compressor is running. If BI08 display remains HI during compressor engagement, then system fault is due to refrigerant.
2. This checks if switch is opening due to low refrigerant pressure charge or switch is faulty.