Possible Causes
WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
A/C PRESSURE SENSOR VOLTAGE ABOVE 4.6 VOLTS
A/C PRESSURE SENSOR
(C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(C18) A/C PRESSURE SIGNAL CIRCUIT OPEN
(C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (K856) 5-VOLT SUPPLY
(K900) SENSOR GROUND CIRCUIT OPEN
PCM