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.

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?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. High pressure side of A/C is low (30 psi)

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: Q: How do you adjust the vents?

Adjusting the air vents in your car lets you fix the flow of hot, cold or fresh air where you want it most. It’s also very simple. Here’s how: Front Right and Left: Move the vent slide left or...

Q: My compressor went out. Will that cause my engine to not operate?

Hello. If you have an engine that is cranking but not starting, then you need to look on dashboard to see if the theft light is flashing first. If it is, then try a different key to see if that...

Q: My air is blowing cold-hot-cold-hot-cold-hot...

It is possible that you have a leak in the AC system. There are pressure switches that will turn off the compressor if the pressure is too high or too low. The low refrigerant level could cause the AC compressor...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.