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Older Model S A/C Service Considerations

Looking for a few things. Mostly related to the end goal of getting my A/C serviced, as it's not cold anymore, but I'm always learning about service on my 2013 Model S so I tend to try and dig a little deeper and now have a few questions that I couldn't find answers to so far. I did look a little through the threads but didn't scour as I'm burning out on research on this topic at this point. So, apologize in advance if there's already an answer - but if you happen to have the link to throw my way it would be greatly appreciated.

Question 1: We have a 2013 Model S 60 we purchased used in 2018 with 70K miles on it. We now are at 120K. No Tech Package but we did have the MCU updated to MCU 2 a year or so ago and very happy with it. This leads to the first question. My understanding is that Tesla Toolbox 3 is only available for MCU's that are the Tegra ones, and not the NVIDIA. If that's the case... and we have a new MCU 2 (Tegra) then I'm thinking I can connect and use Tesla Toolbox 3 even though we have an older car. Has anyone done this or know about it? I'm probably not going to purchase it but it's interesting to know that it might be an option some day.

Question 2: The reason I ask about the Tesla Toolbox option is that the service manual says you need it in order to get into HVAC service mode. This is per the Service Manual guide that I have (probably most older car owners have the same one). My real question is to understand just what this does from a technical perspective to decide if it's important enough. I've seen SO MANY videos/posts about folks servicing their A/C and nobody mentions doing this. So, my curiosity is to try and understand what HVAC Service Mode does and why its needed.

Question 3: This is really the final goal in that I just want to service my A/C and have some options - going DIY, using a non Tesla shop that probably doesn't have any knowledge of Tesla Toolbox let alone the procedures for proper 'Tesla' servicing of the A/C but can service A/C's fairly competently, or just go to Tesla Service and pay the $$$. I don't mind paying - if I know the work is worth it.

Anyone with factual advice on the three above items would be great. If you have opinions, great, but please also provide some evidence to back up your perspective. Not looking for folks that just 'go for it' without understanding the risk. I've serviced my own brakes, replace the sway bar links, etc... so can handle DIY repairs just fine.

Thanks in advance for any info shared.


Well-Known Member
Mar 10, 2016
Unless you have the equipment necessary to recover any remaining refrigerant and pull a vacuum, this is simply not a DIY job.

My advice, and what I recently decided to do for my own AC service despite my DIY inclination - ask Tesla to replace the desiccant bag. This service involves a full evacuation and recharge of your AC system. Total cost for a vintage Model S as of 2 weeks ago: $334.

Not chump change, but it’s done right and a lot less expensive than a compressor replacement if you don’t do something right, introduce unnecessary moisture into the system, etc etc.

My AC performance has improved dramatically since having this done.


Regarding your MCU question: “Nvidia” and “Tegra” refer to the same thing - MCU 1. MCU 2 is an Intel Atom based processor.
Ah. Ok. Nice. I had never heard of the desiccant bag servicing. Looking at the service manual it does say to replace every two years:
Note: The desiccant bag in the receiver dryer is a serviceable item and must be replaced every 2 years, whenever the system is opened to ambient air for an extended time, or when an A/C system leak has been fixed.
I definitely will go that way with Tesla service. Considering I don't think the A/C has been serviced at all in 9 years I'm not upset with a $334 bill to possibly get it back in acceptable working condition. We'll see how the compressor holds out from there. Excellent info! Much appreciated.

My bad on the NVIDIA Tegra names as you are 100% correct that they are the same thing. I didn't pay attention to myself, nor check my info, prior to naming them - I just went by memory. However, looking at my invoice I confirmed I have the Intel MCU, which as you pointed out is Atom based. So, theoretically, I should be able to use Toolbox 3 (if that need ever surfaces).

Thanks again for the reply and providing the cost breakdown details from service.
Many thanks for this thread -- I've had my a/c recharged once, about a year ago, and now it's back to poor cooling. Could be a leak, but I'll see about getting the desiccant bag replaced first.

That is, if my SC doesn't tell me I need a whole new system/compressor/etc. We have recently had an SC "move" in our county (I think they actually fired the old staff and hired all new), and now they seem to be... vampirous incompetents? We shall see.

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