Both High- and Low-pressure Sides are Too High

WARNING: This page is about a different car, the 2005 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

PROBLEM SYMPTOM TABLE - AC SYSTEM (BOTH HIGH- AND LOW-PRESSURE SIDES ARE TOO HIGH)

Gauge indication	Refrigerant cycle	Probable cause	Corrective action
Both high- and low-pressure sides are too high.	Pressure is reduced soon after water is splashed on condenser.	Excessive refrigerant charge in refrigeration cycle.	Reduce refrigerant until specified pressure is obtained.
	Air suction by cooling fan is insufficient.	Insufficient condenser cooling performance. ↓ 1. Condenser fins are clogged. 2. Improper fan rotation of cooling fan.	Clean condenser. Check and repair cooling fan as necessary.
	Low-pressure pipe is not cold. When compressor is stopped high-pressure value quickly drops by approximately 196 kPa (2 kg/cm² , 28 psi). It then decreases gradually thereafter.	Poor heat exchange in condenser. (After compressor operation stops, high-pressure decreases too slowly.) ↓ Air in refrigeration cycle.	Evacuate repeatedly and recharge system.
	Engine tends to overheat.	Engine cooling systems malfunction.	Check and repair engine cooling system.
	An area of the low-pressure pipe is colder than areas near the evaporator outlet. Plates are sometimes covered with frost.	Excessive liquid refrigerant on low-pressure side. Excessive refrigerant discharge flow. Expansion valve is open a little compared with the specification. ↓ Improper expansion valve adjustment.	Replace expansion valve.