DTC P1543 - A/C System Performance: Notes

NOTE: For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .

PCM monitors A/C refrigerant pressure and A/C evaporator temperature to determine if A/C system has adequate refrigerant charge. PCM will disable A/C clutch whenever refrigerant charge drops to less than a predetermined value, to reduce chance of compressor damage. PCM will cycle compressor more frequently if charge is slightly low. PCM determines A/C charge based on refrigerant pressure and evaporator temperature. PCM uses these 2 inputs to calculate A/C refrigerant charge.

DTC will set when following conditions are present:

PCM calculates refrigerant charge to be below a predetermined level.