Prius 2009 Air conditioning issues

So just on the low side if you put one of those stupid cans with the gauge on top of it you remove the gray cover on the fat hose marked l for low side and you click the can in place You've not even punctured a hole in the can yet You're just using the gauge what do you see cars not running what's the number on the gauge Is the gauge buried past its reading capability? It should be on a non-running air conditioning system of this type there is no high and low side with the vehicle and the system not running so you're high and low side ports should show the same pressure Very close to 100 lb 9088 somewhere in there It's off the scale of the low side gauge that came with the can correct? If so have someone else get in the car bring up the screen for the heat and cooling put it on LO fan on high blowing out the vents at your face and then have them hit the air conditioning AC and make it yellow The minute he hits the AC and makes it yellow you will hear the compressor start The gauge that's connected to the can that's connected to the car should now pull down to about 36 PSI very quickly. The hose that this gauge and can are connected to should now start getting cold In a few seconds you should notice some light changes on the gauge but nothing really significant it'll bounce around a little bit 36 to 40 maybe down to 32 You should also in your sight glass generally see no bubbles maybe every 10 seconds a bubble might float by the sight glass moving away Is this happening? The hose is getting cold noticeably so almost freezing everything seems to be working correctly now it's inside your car you're not getting any cold air but the fan is running maybe you need to check the electric device that moves the damper door from heat to cold or something along those lines. If only some of this happened you can get a real set of gauges and connect up to the high side where you should see something like 36 lb on the low side that side should start getting cold but then again when you have your full game set hooked up if you're high side is not pumping up 250 somewhere around there on a 90° day and it's extremely lower gauge reading than that 140 then your compressor may not be up to the task of creating the refrigeration cycle.

 

That's the outdoor temperature sensor there's a little place for it to stick into the metal on the piece that goes from the upper core support to the lower core support generally right past and under your latch mechanism I think and cross the middle of the radiator down to the lower core support or crossmember and there you'll see a little rectangular square cutout and I believe that temp sensor goes there this is what tells you your temperature on the MFD when you're sitting inside the car and you'll know it's 105° outside Don't know if it has a whole lot to do with the air conditioning but I imagine it tells the air conditioning computer The temperature which it might need to know. I find this interesting that pusher fans or puller fans or anything fans are making everything happen usually I'm flying down the road reasonably quick enough to air flow is the least of my air conditioning issues of course unless the fans aren't running but I guess it speed with the air on they're running but even if they were switched off if you had a switch to do that as long as you're maintaining 40 miles an hour plus you should have ample cooling of the freon just by the movement of the car not when you stop at a stoplight but when you're going down the road say 35 37 up.

 

There seem to be different issues going on here. The initial failures were probably due to the inverter pump not working. As the inverter overheats it shuts things down, and one of those is the A/C. Now that the pump is working. ..

Wait, stop. Is it an OEM pump? If not don't assume that the problem is fixed, the non OEM pumps have a very high failure rate. At least check that the coolant in the inverter reservoir is agitated now and the next time there is an A/C problem (I had a Dorman pump which would fail to start sporadically, it was like having a dead inverter on some drives and a working one on most others.)

Back to the A/C. Is it losing refrigerant? You do not want to run it when it is low on refrigerant, that will destroy the compressor. If it is leaking and the shop cannot find the problem in the engine bay then it is likely a bad evaporator. That is built into the center of the dash and is both an expensive part and a PITA to replace. Many hours of work to do so. First priority though - be sure that there is refrigerant in the system if it is turned on. Also be aware that the Prius has special needs with respect to its A/C system, it cannot just be recharged with a can of freon from the auto parts store.

If the fans are not coming on that is another problem. But as Tombuk2 said, if the car is moving 40 mph or so the fans shouldn't matter because plenty of air will be forced through the radiator just by the motion of the car.

 

I have never had to go through any of that nonsense at all here in the US so maybe there are problems in other parts of the world usually the system is low on refrigerant and I top it off with the system running till the sight glass is almost clear at full tilt generally that is resolved every issue in the five that we've had here in the last several years all of them are still working today none of them have had to be drained new oil put in and refilled by any special equipment measuring grams or pounds I think these cars hold about 1.2 lb of refrigerant gas 134a something along those lines so that's about one can and a shot out of the second can if you will so there's always that I mean if you want to pay for those services and that's what you have to do because you can't do this or what have you then well by all means sometimes people make this stuff way too much technical than it really needs to be refrigeration and air conditioning in the Prius is very similar to a belt driven compressor off the crankshaft It's just now we have the luxury of pumping the freon gas for the refrigeration cycle with an electric motor pressures and all that still have to be almost identical to the belt driven crankshaft driven compressor so this really not much difference in the whole mess unless you have a leak in the evaporator or some other hard to get to location which is going to render you and a 3000 plus dollar repair might not be worth it and you've added pusher fans to push more air through the puller fans or did you remove the puller fans from the factory and add pusher fans and if so why I don't think your add-on I can't even think of the big name now of the company that everybody uses for the electric fans I have a few of them hanging here but the name's not on them anyway. I can't imagine adding another big fan in front of the condenser pushing through the two polar fans mounted behind the radiator it just seems like not a thing You're almost adding more blade blockage and whatnot but that's just me the Toyota fans have always been ample they're relatively inexpensive now if you remove the polar fans and you want to put spax that's the brand name. Then by all means have at it I think you can get high or CFM and more air flow and two spax with the special fittings that pull the fan right up to the radiator or core surface that might be the ticket but I've never needed that in the 100° heat in North Carolina so I can't imagine.

 

Hey, that part's actually true kinda—'cause the gen 1 Prius did have a belt-driven compressor off the crankshaft, but even gen 1 already had the subcooling condenser design, which is why the proper refrigerant charge had to be given as so many grams past the sight glass clearing up, and why it was already so easy to charge wrong if not evacuating and using a scale.

 

I guess I must be very lucky because I've had to empty a few and sometimes I have access to a vacuum pump sometimes not when I do all vacuum it down and when I don't sometimes I'm not even using 134a I'm using I've mentioned it here before but I can't remember what it's called now but it's nice cold refrigerant it works well and the 134A system a little bit less head pressure etc either way all of them work great I haven't had trouble with anything have it measured or been to a professional AC shop or any of that actually I don't think ever in my life oh well as long as everybody has cold air when they need it that's the main thing and hopefully you don't have to mess with your evaporator whichever car you have I'm sure they're all very aggravating won't like a Corolla which you can do in about an hour and 20 minutes

 

If anything it would seem like you're a little low which would stall some of the refrigeration cycle I guess It wouldn't be a little low I guess it would be a bit low and you should note that in what you see in the sight glass foam bubbles etc so that tells you there is moisture in the system etc at this point a good vacuuming is probably in order and possibly a receiver dryer if that's a thing that can easily be done on the Prius I think you have to change the condenser or it would have to be squeezed in by somebody that knows how to work with the piping for most it'll just be a condenser replacement I think and then you would vacuum that new system down and shoot in whatever gas is your preference at the time and let it rip and then make sure you don't have any leaks inside the car tested extensively to make certain of this most of the a lot of these cars have this evaporator problem in a little bit of gas escaping equals very little cooling quite quickly like I say all four of mine which have had none of these heavy duty antics done to them at all all work fine in the North Carolina hundred to 110 plus degree temperatures in the summer I have no complaints It's not like a big general motors Cadillac or van or anything like that but it is quite adequate considering the fuel usage and what have you dress for the weather if this is your problem put on your suit when you get to your office maybe whatever