2013 Model S 85 AC hissing noise and warning on MCU

[brooce]

So, my problem child has another.... problem....

Just got back from 2 weeks away, car sat quietly asleep while I was gone, wasn't plugged in but didn't get below 60% charge and weather in Durham was between 32-60 degrees during this time. Car updated to 2019.40.2.1 while I was gone.

Get in to drive it around 5am, it was cold ~45 degrees, so I turn on seat warmers and screen defrost, nothing unusual. A few minutes later ( I wasn't paying attention) I get a message on the screen "Air conditioning reduced DC fast charging/ Supercharging rate may be reduced". The message went away again after a few minutes and some time later in my 2 hour drive it reappeared and disappeared once more, by this time the outside temperature was pretty warm ~60 degrees or so.

When I got to my destination I checked the AC by setting it to low and it blew warm air, I then did several resets and each time the AC still blew warm and while ever the AC was switched on there was a loud hissing noise that sounded like it was behind the dash and couldn't really be heard outside the cabin, disappearing again when I turned the AC off.

It's been over 24 hours and 200+ miles since the problem appeared and it's not gotten any better.

I have an appointment booked at Raleigh SC on the 23rd, apparently they're busy, in the meantime any clues what this might be or how to troubleshoot?

 

[brooce]

Did I post this in the wrong place or something?

 

[brkaus]

All I could come up with was our mean cat was stuck in your dash. Checked her bed and she was still there, so I'm out of ideas.

 

[brooce]

All I could come up with was our mean cat was stuck in your dash. Checked her bed and she was still there, so I'm out of ideas.

Fair comment. Cat is nowhere to be seen, will investigate further.

 

[BrownOuttaSpec]

Did I post this in the wrong place or something?

I would guess that no many people have seen the problem before so no one has any good suggestions other than do what you are doing to schedule an appointment.

 

[brkaus]

If it isn't cooling, it's likely the compressor or the DC2DC convertor (or both). I cannot explain the hiss. Sometime AC units will make some sort of bubbling/hissing sound when turned off and they are equalizing.

I't does not sound like something simple like the fan making the noise.

It also could be (but unlikely) -
- Accuator inside the cabin used to direct air broken
- Fan inside stuck/something in it
- Outside louver not opening (but not likely as it normally opens when it is super hot out)

I say unlikely as these typically hit the inside system, but I don't think they would effect the battery cooling loop.

 

[PWlakewood]

Ac refrigerant may be low. Had this happen over the summer and brought into sc and all they did was refill and pressure check ac system. Problem fixed. They had originally told me it was the compressor and dc/dc converter but I asked alot of questions and pushed back. Turned a 3400 quote into an 84 dollar fix. Might be worth your time to just go pick some ac refrigerant up and refill yourself. Easy and simple.

 

[brooce]

Ac refrigerant may be low. Had this happen over the summer and brought into sc and all they did was refill and pressure check ac system. Problem fixed. They had originally told me it was the compressor and dc/dc converter but I asked alot of questions and pushed back. Turned a 3400 quote into an 84 dollar fix. Might be worth your time to just go pick some ac refrigerant up and refill yourself. Easy and simple.

This is my suspicion too, but it just seems a bit convenient given that it was working and then died while not even in use for 2 weeks.

Did they track down the source of your leak?

 

[PWlakewood]

No leak detected and I haven't had any issues for 6 months. Doing it yourself will only cost you 20 to 30 bucks and if it doesnt work then you know its something more serious. If it does solve the problem you just saved yourself money and a huge headache dealing with service at tesla.

 

[brooce]

No leak detected and I haven't had any issues for 6 months. Doing it yourself will only cost you 20 to 30 bucks and if it doesnt work then you know its something more serious. If it does solve the problem you just saved yourself money and a huge headache dealing with service at tesla.

You're right - system only had 0.18lbs of refrigerant left in it! No leaks found, (not sure how hard they looked, they were pretty quick) system refilled for $175 + tax.

It seems to be working again now, guess time will tell.

 

[PWlakewood]

You're right - system only had 0.18lbs of refrigerant left in it! No leaks found, (not sure how hard they looked, they were pretty quick) system refilled for $175 + tax.

It seems to be working again now, guess time will tell.

The refrigerant has to be going somewhere but I guess it's better than the dc/dc converter going bad. Glad to hear its fixed

 

[Obsoletion]

You're right - system only had 0.18lbs of refrigerant left in it! No leaks found, (not sure how hard they looked, they were pretty quick) system refilled for $175 + tax.

It seems to be working again now, guess time will tell.

If no leaks were found, where did the refrigerant go? That would have been my only question and then wouldn't have paid as it was obviously low from the factory... you know, because there are no leaks...

 

[brooce]

If no leaks were found, where did the refrigerant go? That would have been my only question and then wouldn't have paid as it was obviously low from the factory... you know, because there are no leaks...

Ha! I'll remember that line for next time... For it to go from functional to not, clearly it's leaking, how badly I don't know. I wanted to talk to the tech that did the job in order to ascertain this, but he was nowhere to be found by the time I got there, so the question was left with the guy at the desk. Will I hear back from Tesla on this? Probably not. Will Tesla hear back from me? Highly likely, especially seeing as though my car now has a peculiar smell coming from the a/c vents...

 

[Alysashley79]

Ha! I'll remember that line for next time... For it to go from functional to not, clearly it's leaking, how badly I don't know. I wanted to talk to the tech that did the job in order to ascertain this, but he was nowhere to be found by the time I got there, so the question was left with the guy at the desk. Will I hear back from Tesla on this? Probably not. Will Tesla hear back from me? Highly likely, especially seeing as though my car now has a peculiar smell coming from the a/c vents...

They probably spilled the refrigerant when they filled the system. I’d roll the windows down and let the system run for a bit to burn it off.

 

[PWlakewood]

I only paid 83 bucks but it's been fine for over 7 months now.

 

[taimurasad]

Ac refrigerant may be low. Had this happen over the summer and brought into sc and all they did was refill and pressure check ac system. Problem fixed. They had originally told me it was the compressor and dc/dc converter but I asked alot of questions and pushed back. Turned a 3400 quote into an 84 dollar fix. Might be worth your time to just go pick some ac refrigerant up and refill yourself. Easy and simple.

were you also hearing hissing sound with low cooling when this happened to you?

 

[PWlakewood]

were you also hearing hissing sound with low cooling when this happened to you?

I don’t think so but it’s been so long ago now.