Note. For circuit reference, see WIRING DIAGRAMS article.
Circuit Description
PCM uses 5-volt reference "B" circuit as a sensor feed for A/C refrigerant pressure sensor. PCM monitors voltage on this circuit. If PCM senses voltage out of tolerance/range, DTC will set.
Conditions required to set DTC are, PCM detects an out of tolerance condition on the 5-volt reference "B" circuit and condition present for longer than 10 seconds.