A/C compressor not making pressure.

RETIRED TECH

MEMBER
2011 HYUNDAI SONATA
2.4L
4 CYL
2WD
AUTOMATIC
105,000 MILES

Hi
I put a set of gauges on the car and the hi and low sides read the same, about 80 psi. I see this car uses a compressor that is always turning, with an electronically controlled flow valve. I suspect the compressor is no good. I disconnected the wiring from the compressor and read the voltage. It read 4vdc. Is 4vdc enough to control the electronic control valve? Is the valve itself serviceable? Thank you for the help.

5 Replies

HMAC300

MECHANIC
48,601 POSTS

If it's reading 80 on both side compressor is either bad if it's turning or it' s not working. Check items in pic first as it ma not be what you think. Then have it scanned by a pro to see if control head is bad. Also have it checked to see if there is a full system or not as it may not be. If this is auto temp control where you set the temp then it has to be scanned first due to it can be any sensor that is not letting the compressor work and that may be the problem. There are two switches one is what called a triple switch that tells the thermostatic switch whether to turn on or not. So that has to be checked as well.

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Friday, June 5th, 2015 AT 10:28 AM

HMAC300

MECHANIC
48,601 POSTS

Sorry I s the wrong info on fuses and relay, please disregard first diagrams as these are correct. The other info though still pertains.

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Friday, June 5th, 2015 AT 10:34 AM

RETIRED TECH

MEMBER
3 POSTS

I too am a retired tech. I'm sorry to say I found your answer lacking. In that you never really answered my question. How many volts controls the Electronic valve? As I stated, the compressor input shaft spins the entire time the engine is running and there is a belt on the pulleys. It appears, Hyundai now uses an electronically controlled spool valve (built into the compressor) limiting the pressure to only that which is required. Saving fuel in the process.

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Monday, June 8th, 2015 AT 12:02 PM

HMAC300

MECHANIC
48,601 POSTS

Sorry I goofed it should be 5v but we have absolutely no info if this is electronic or whether it can be repaired. I dont' see it in rock auto. Has it been scanned for codes? I'll hand this off to someone else to see if there is a better answer.

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Monday, June 8th, 2015 AT 12:29 PM

RETIRED TECH

MEMBER
3 POSTS

Thanks for the follow up. As a retired tech. This system is new to me. My Mitchell Ondemand shows the wires for the electronic control valve coming direct from the A/C control module. Since control modules operate on less than system voltage, I felt 5 vdc would be acceptable.
I just didn't want to put a compressor on the car and "hope" it would fix it.
Thanks again, Matt