Hello, the problem is varies high and low pressure

checked for a problem nozzle, low inlet water pressure to the pump or faulty pressure regulator.

The pressure of the refrigerant in the systems vary depending on the temperature of the refrigerant gas and the type of gas used. So this is a question that can't be answered without a lot of additional information.

PO961Is Pressure Control Solenoid A Control CKT Range/Perf.

DTC P0532: Air Conditioning A/C Refrigerant Pressure Sensor Circuit Low Voltage.
The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The ECM supplies a 5-volt reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the ECM to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is high, the ECM commands the cooling fans on. When pressure is too high or too low, the ECM will not allow the A/C compressor clutch to engage. P0532 Chevrolet Refrigerant Pressure Sensor Circuit Low Input

Thats a hard question to answer! what Type of refrigerant is in it? R-22 or R410A? If its R-22 you want to see about 60-65# low side and 225 -240 high side. those can vary with outside temperature. R-410A look for 120# low side and 450-475# high side. DO NOT USE R22 MANIFOLD SET ON R410A SYSTEM!! IT WILL NOT TAKE THE HIGH PRESSURES AND COULD EXPLODE.

If your 2003 Impala had a low pressure switch it would shut off the compressor if the low side pressure got to low. This would indicate that there is not enough refrigerant in the system an therefore not enough oil flow through the compressor so the compressor is shut down.

The high pressure switch, if your impala had one, would turn on the fan once the a/c pressure on the high side reached a certain pressure.

Switches are just that, they are either on or off. A low pressure is normally on and a high pressure is normally off (this can vary greatly depending on the car).

Your impala uses a pressure sensor. The sensor reports actual pressure data to the PCM which combines info from other sensor to determine what should be turned on and when.

Hope that helps. If you have any questions let me know and I'll see if I can answer them for you.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

low side should be about 30 psi at idle speed, high side 120 to 180 psi depending on ambient temp. higher temp, = higher pressure, as you increase engine rpm to say 1000 low side should drop to 10 to 15 psi & high side should increase about 30 psi. If high side goes over 280- 300psi you have contamination (air) in system or over charged with refrigerant. you will need to recover freon, evacuate & recharge system with proper amount of refrigerant. If the low side drops below 0psi or into vacuum then the refrigerant level is low, you will have to check for leaks , repair leaks & refill refrigerant.
Hope this helps
Paul T

Hello, what is your high side pressure? A bad compressor will show abnormally high low side pressure with abnormally low high side pressure. That 45 low side pressure is low And superheat high. If you high side pressure is normal toma little above normal but the low side remains low you have a restriction in the system, that might be why it's not taking in tne freon. Let me know you high side pressure

Sustion or low pressure depending on indoor temp about 70-75 head pressure will vary with a,bient temp. But no moe than 260 to 275. Rus

28-32 low side, 150-175 high side, but these are approx, varies with air temp and humidity..