Skip the auto shop - Our mechanics make house calls

Q: High pressure side of A/C is low (30 psi)

asked by on

The air compressor low side is at its normal psi. It kicks the compressor on and off between 26 and 30 psi. The high side does not move and it is at 30psi. It should be at 220psi. There are brand new expansion valves so those have been factored out as the problem. The condensor works properly. There is also brand new low pressure and high pressure switchs. Also a brand new trinary switch. All are in working order. What could possibly be making the high side such a low psi? We also charged the system anywhere between 3lbs and 6lbs. That has done nothing to the pressures at all.

A: Hi there. It sounds like the AC compressor ...

Hi there. It sounds like the AC compressor internal valve or the compressor itself has failed and is allowing refrigerant to sit freely and preventing pressure from accumulating; no suction and no discharge equals same pressure on both sides. You could also have a failed ac clutch or relay not engaging the compressor. I strongly suggest asking a qualified technician to perform an inspection to avoid replacing unnecessary parts. YourMechanic has several technicians available who can assist you with an AC does not work inspection.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How do you use the heater and air conditioner?

Depending on the trim level of your car, you have either a manual heater and air conditioner or an automatic climate control system. If your system is manual, here’s how to use it: Heat: To turn on the heat,...

Q: Where can I find an A/C compressor clutch (compressor is fine).

Hey there. You may be able to find a complete clutch at an aftermarket parts store. The compressor with a new clutch may be a better choice since they are most likely available and cheaper then purchasing the clutch parts....

Q: Air conditioner doesn't work

The AC condensers on these cars are known to leak, according to most owners that have had AC problems. Diagnosis of the inoperative AC depends on inspection of the AC condenser for leakage. The AC condenser is in front of...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.