Help diagnosing poor AC performance

[ucmndd]

It’s getting hot here in interior California and I’ve been noticing my Dec 2016 Model S is not coping particularly well. It’s been north of 100 degrees the past week and I’m noticing relatively poor AC performance, along with fairly regular errors stating “cabin AC temporarily reduced, vehicle systems being cooled”.

Additionally if I start charging my car at home on my wall connector shortly after driving, the fans start running full blast in what I can only interpret as an attempt to cool the car/battery while charging. This never happened before.

I scheduled an appointment with Tesla and they want nearly $400 to do basic diagnostics and evac/refill the refrigerant as a first step. I had the desiccant bag replaced less than a year ago, which includes a refrigerant evac/refill, and there was no noticeable difference in output/performance, so I’m reluctant to give them a bunch of money to do the same thing again. I got frustrated and just cancelled the appointment.

Recently recalled there was a thermal test in service mode so I decided to give it a try. It looks like the left and right radiator shutters failed, which seems like it could explain a lot of my issues. I’ll probably try and replace those myself or see if I can just direct Tesla to do that work without all the other diagnostic BS.

Main question I have is there was one other failure for “temperature sensors”. Does anyone know what exactly this is or what it might entail to address? Appreciate any insight.

 

[ucmndd]

Apologies, I intended to post this in the Model S forum. I’ve asked a moderator to move it.

 

[brainhouston]

If shutters don't open ur condenser will overheat n cause cold side to be less cold so it's a good start.
My guess would be maybe it refers to refrigerant temp sensors?..
Do u see it on SMT?

 

[ucmndd]

If shutters don't open ur condenser will overheat n cause cold side to be less cold so it's a good start.
My guess would be maybe it refers to refrigerant temp sensors?..
Do u see it on SMT?

I do not have SMT. Thinking that might be my next investment.

Cabin AC temp is actually decent most of the time until the error pops up about diverting cooling to the “vehicle systems” (i.e. battery). Radiator louvers being stuck closed seems like that might be what’s causing that to happen, keeping coolant temps higher than they should be and forcing the AC to work harder and divert precious cooling away from me in the drivers seat.

 

[ResHacker]

All of my 4 shutters doesn't work but at least the rad ones probably stays open as when charging on SuC the side fans are blowing at full speed sucking air through the radiator. So apart from the loud sound I don't feel any doscomfort but want to solve it anyway..

 

[brainhouston]

I do not have SMT. Thinking that might be my next investment.

Best $8

All of my 4 shutters doesn't work but at least the rad ones probably stays open as when charging on SuC the side fans are blowing at full speed sucking air through the radiator. So apart from the loud sound I don't feel any doscomfort but want to solve it anyway..

Shutters/louvers are not air tight so fan will still pull air thru, just gets less efficient overall...

 

[vcor]

I vaguely remember that the shutter errors are not real and are a minor service bug. It may depend on the era of the car. It was something like the shutter sensor doesn't exist on the car, so the error appears. Anyway, I'd try and confirm if the shutters are really broken before wasting money fixing something that isn't broken. I think there is plenty of airflow, even if the shutters are closed, so I doubt that would prevent the HVAC from working. I'd focus on the "Temperature sensors" not working, but I don't know which sensors the diagnostic refers to and they could be a phantom error too. Hopefully, someone else with more knowledge of HVAC repairs can chime in.

 

[tldickerson]

I don't know if this will help but I recently learned that there is a button that needs to be turned on in your center screen display of the air conditioning system. The button is just right of the fan speed settings. Make sure that's turned on. I just went and checked mine after getting a update yesterday. I've also noticed that after some updates that some of your air settings change on their own. My vents often change from what I was using to another option. Mine had changed from the dash vents to the floor vents. Always need to check that too.

 

[ResHacker]

I vaguely remember that the shutter errors are not real and are a minor service bug. It may depend on the era of the car. It was something like the shutter sensor doesn't exist on the car, so the error appears.

Yes, I believe it's something like this, there were also opinions from service techs here that some louver re-synch or calibration sequence should solve this issue. Will try to run old Toolbox on my car and then test it..

 

[brainhouston]

I don't know if this will help but I recently learned that there is a button that needs to be turned on in your center screen display of the air conditioning system. The button is just right of the fan speed settings. Make sure that's turned on.

This?

Thats re-circulation button, you'll notice it will automatically turn on if u increase fan to like 8-9 i think

 

[maximizese]

I think a lot of us have been getting the shutter alerts in Service Mode as of late. I ran the thermal test and got a failure with the Shutter Right Radiator despite seeing the louvers and fan operating just fine. I'm going to do the latest FW update tonight and will bring my FLIR thermal imaging camera with me for my next Supercharging session to check the temperatures of both sides and see if there's any significant difference in heat soak from the left and right sides.

 

[NewbyMaybe]

If the louvers are shut when the fans are blasting then prop them open and see if it helps?
How do you confirm refrigerant is good?

 

[ucmndd]

If the louvers are shut when the fans are blasting then prop them open and see if it helps?

The condenser shutters, the ones you can easily see from the outside, seem to be working fine. It’s the interior ones on the center radiator that are throwing errors. Sounds like I need to rip into the frunk to verify their operation, which I suppose will be the next step.

 

[Artys2123]

Hello did anyone figure out what temp sensors this refers to? I also had similar codes and the radiator shudders just needed to be resynched. But I cannot figure out the temp sensors failure issue