Code 123, Low A/C Refrigerant Pressure: Notes

Code will set if engine speed is 500 RPM or greater for 20 seconds, PCM monitors an A/C request on serial data line for 30 seconds and Code 135 is not set.

NOTE: Test numbers refer to numbers on diagnostic chart.

Checks which side of switch circuit needs diagnosis.
Checks to see if A/C low pressure switch circuit, PCM terminal or PCM are at fault.
Checks if problem is electrical or refrigerant pressure related.