Automotive Air Conditioning Information Forum

Hi guys,

My 2011 Camry A/C has me stumped and it's getting kinda toasty here in Central Florida. I need some help figuring this one out.

Car has about 190k miles on it, original compressor, variable type. It will cool at the beginning of a commute but then stop cooling. When it's running the manifold gauges show reasonable low and high pressure ranges, when it stops cooling the low pressure starts rising and the high pressure starts falling.

When the not-cooling is going on the OBD reader shows a regulator current over .9 amps, which seems to be the "don't try very hard, or maybe not at all" range. When it first turns on it will drop into the .7A range, which seems to be the "try harder" range, then it will slowly climb, stopping short of the .9A range and continuing to cool. Eventually something happens, seems like engine demand changes may trigger it, the current will climb to the .9A range and cooling stops. Five minutes or so later I'll accelerate (or something) and start a new cycle of cooling, but usually not for long.

The intermittent behavior seems like freezing up, but the low pressure doesn't drop when the cooling stops and there's no "wow, this thing is making ice cubes" stage right before it stops. It seems like the compressor is being told to stand down.

This is my first time working with a variable compressor, so my theory of operation may have holes in it. Suggestions?

-- Carl

A couple of thoughts come to mind:
The problem could be as simple as a low refrigerant charge. Has the A/C ever been serviced--that is, recovered, evacuated, and recharged according to the exact weight-of-charge?
It could also be the control valve that's acting up. If so, and with that kind of mileage on the car, the compressor might be "tired" as well. In such a case, consider replacing the entire compressor, along with the desiccant bag inside the receiver/dryer.

Following up... Took it to an AC guy, he diagnosed it as bad compressor. Replaced compressor, condenser coil, and receiver dryer. Makes ice cubes now, thanks!

-- Carl

Glad you got it sorted out and that it's cooling well again. Just in time, too.

Probably was the control valve that was malfunctioning, but with that much mileage on your Camry, I think it was a good call replacing the entire compressor, plus the condenser and R/D, which are typically replaced to maintain the manufacturer's compressor warranty.

Now you know much more about variable displacement compressors

It's a lot easier to understand when you have a working system to monitor. I now know what "good" looks like via OBD scanner.