A/C cold while driving, warm while idling

So look at the sight glass have someone else drive the car with the hood partially unlatched I do this so I can get it up quickly without having to wait for the person doing the driving to pull the lever but no matter. Have them drive up and down the street air conditioning cold now they come pulling up to you and stop you whip up the hood and look at the sight glass You got to do this fast. What do you see in the sight glass You may just be seriously under charge enough so that when the car is going down the road and plenty of air is coming in You're making what you think is enough cold and then as you slow the car down and there's not very much air coming through the front of the car cooling the gas it's performance plummets I guess this is possible The gas is a fine balance and that's what I would be checking first and then another check that's kind of easy to do is if you can get your hand up onto the condenser that's the part in front of the radiator that cools the freon after a good run and you pull in the driveway or over to the side of the road if you were to get where you can get your hand on the condenser is the condenser the same temperature more or less all the way across it are there any hot spots?

 

Get a diagnostic scan asap so that you can pin point down the issue quickly. If you let DTCs build up, it will be hard to pinpoint the culprit problem that is causing issues to other systems.

 

Since it’s an electric motor driven compressor engine speed is not much of a factor. Both radiator fans need to run. A quality scanner can test their low and high speeds.

Measure the vent air temperature while driving. A very good system that is cooling the car well may get down to 45f. Odds are yours is more like 65-70f. If so it’s low refrigerant typically although the condenser may be blocked or the metering device has failed.

 

If you don't run the air you shouldn't have any problems with DTCs until other things are failing besides the air conditioning it's not even on. I run cars for one or two seasons without the air working no matter till you try to turn it on and if it's connected to your computer system well you'll get notifications that it's not working or codes.

 

I'm just speaking in general. The main ECU does quite a good job at detecting any type of faults in any system. But if you let DTCs build up, it becomes more of a headache in diagnosing the main culprit.

 

You can get a lot of duplicate comm errors combined with issues that are side effects of a root cause. Often experienced guys save current snapshots, clear everything and go from there. Bottom line is the best legal Techstream with interactive documentation and live links still requires comprehensive training of hybrid systems first. Which in most cases may be only one Master Tech per dealership and selected independents who often were trained at a dealership.

The saving grace is most issues repeat and are seen often.

 

AC cold when moving, hot when stopped, is the classic symptom for malfunctioning front cooling fans.

 

Yes ready the car put on the air conditioning get out of the car lift the hood after pulling the hood release. And the fans should be on by default when the air conditioner pump is pumping gas so if your air conditioning compressor is on you can put your hand on it feel the vibration there's no belt remember it's electric If it seems to be running touch the fat hose the metal silver line and see if it's getting a little cold If that air conditioning compressor is running the two front fans should be pulling air through the radiator and blowing back against your hand and then the engine pretty smartly You should hear them if they're running and you don't hear them but you can see that they're running they may be on their last leg meaning they need replacing because they should be running quite smartly and in between the engine cycling and the business going on you will hear the fans and feel the air if you stick your hand behind the fan or in between the fan rear and the engine front which there's no moving parts down there to hurt your hand none The grills are over the fans you can't get your hands or fingers in there generally speaking unless you're really trying and if you can't feel the air you need to find out why the fans are running too slow they may be clogged with crap in them they're not very expensive to begin with so if you're not in the third world country and have other choices it may be cheaper just to replace the fans or the fan motors as the case may be so if you're not in the third world country and have other choices it may be cheaper just to replace the fans or the fan motors as the case may be

 

Long shot here but.............
You aren't in the habit of shifting to N when stopped or slowing down, are you ?

The AC compressor runs off of the HV battery.
If the system detects that it is getting weak, it might turn it OFF
on purpose to conserve the battery.

The HV battery will NOT charge when in N.
That is a valuable thing to know when going through a
"drive through" car wash too.

 

It is pretty tight posterior to the fans. Rather than sticking a hand in there slide in a thin stiff piece of cardboard long enough to get down into the fan flow. Like the piece of cardboard on the back of a pad of paper. If the fans are going it will push hard on the cardboard, and if not, no push at all. It might be safe to stick a hand down there on a Prius but best not to get in the habit of poking one's hands in narrow spaces under the hood on running cars - there might be something spinning or hot you weren't aware of.

 

Have you tried cleaning out and straightening out the condenser and cooling fins? If the condenser isn't removing the heat from your R134, that will result in less heat rejection - warmer air coming out of your vents.

When you checked your fans, was it moving a lot of air or just spinning? It needs to move air; to cool your condenser.

 

By "warm" you mean you can put your hand on it and it is above ambient, but well below sizzle and yank your hand back too hot hot? That would probably be normal. Wherever the outlet is will be very hot though normally, because of thermodynamics and the formula PV=NkT which describes the relationship between pressure volume and temperature for a perfect gas. That is, compress a gas and it will heat up. Outlet temperatures should be below 220F or so, but a piece of metal at 220F is in the "burn your finger real quick" range.