B448

Code B448:

Low Refrigerant Switch Circuit:

A/C Temperature /Pressure Relationship:

DESCRIPTION:

In the process of controlling the compressor clutch, the BCM monitors certain system inputs for an indication of low refrigerant charge. The BCM monitors the normally closed low refrigerant pressure switch at pin 1D16. The status of the low pressure switch is checked prior to compressor engagement. IF the return voltage to the BCM indicates the switch is open, the compressor will not be allowed to engage and a code B448 will be set in diagnostics. Additionally, the CCDIC will switch to ECON mode and the A/C low refrigerant message will be displayed.

TEST DESCRIPTION: Numbers below refer to the circled numbers on the diagnostic chart.

1.Checks current state of low pressure switch.

2.Checks circuits to low pressure switch.

3.Checks refrigerant system pressure.

4.Checks for restriction in the refrigerant system.

5.Checks for intermittent short/open.