I replaced my own battery heater

[Palmtree]

It was really cold recently and I got the warnings- car may not restart and acceleration and top speed reduced -- also no regen. Tesla remote diagnosed it as failing battery heater and quoted me $705. My car is out of warranty so I bought a used battery heater out of a 2018 model S and replaced it myself. It was quite difficult to reach everything that is buried under the cowl but otherwise straight forward following the instructions in the service manual.
I decided to do the job yesterday because I had just received notification that 2020.48.37.3.1 was ready to be installed and I had read that if you change a part you need to reinstall the software to remove the warnings and limitations applied (crippled acceleration and no regen). Well the warnings and limitations are still there after successful installation of the new update. Does anyone know why this is? Can anyone help me remove these warnings? According to SMT the battery heater is working fine. It ran at 100% and raised the coolant temp from 57 degrees to 111 degrees fairly quickly. I just need to get the warnings removed.

 

[2101Guy]

sometimes parts are "coded" to a vehicle or need coding. BMW batteries of a few years back come to mind, where dealership had to connect car to computer so that the car properly recognized the new part/battery.
wonder if coding is needed for this part?

 

[Palmtree]

I reached out to Tesla again and told them my situation. This is what they said.

 

[random155]

Stop by the SC with a box of donuts and ask if they have 10 mins to clear the codes.

 

[Palmtree]

Not a bad idea. I live over an hour away though. The plan now is for a mobile tech to stop by the hospital where I work and reset it. Will this cost me more than if I took the car to the service center? Also they aren't coming until March 4th. That seems like a pretty lengthy wait for such a small task. Certainly a long time to drive a perfectly running car that is locked down to prius acceleration and no regen.

 

[sorka]

Not a bad idea. I live over an hour away though. The plan now is for a mobile tech to stop by the hospital where I work and reset it. Will this cost me more than if I took the car to the service center? Also they aren't coming until March 4th. That seems like a pretty lengthy wait for such a small task. Certainly a long time to drive a perfectly running car that is locked down to prius acceleration and no regen.

It won't cost anywhere near $705. You're still way better off having done it yourself.

 

[KyleDay]

I think if you power down your car for 5 min, or disconnect the HV first responder loop and your 12v negative battery terminal for 5 min, then power up car again the alerts will self clear. Make sure to wait 5 min

 

[EZBoy]

You definitely need to power cycle the car with fireman loop/battery disconnect after this type of repair, but I would assume he had done it while changing the battery heater?
Installing new software has updated the firmware on the battery heater for sure, otherwise it would not have worked. I am not sure about HV isolation faults though, fireman disconnect might just do it, please keep us posted!

 

[Palmtree]

I think if you power down your car for 5 min, or disconnect the HV first responder loop and your 12v negative battery terminal for 5 min, then power up car again the alerts will self clear. Make sure to wait 5 min

I will try that, although I did have both of those disconnected for a couple of hours on Sunday while replacing the heater. Does order in which it is done make a difference? Sunday I unhooked the 12v first and responder loop second. Also when you say "make sure to wait 5 min", do you mean I need to wait exactly 5 min, or at least 5 mins?
The service center said they would charge 30 minutes labor to clear the codes -- so $75.
BTW, I bought the 2018 battery heater on ebay for $55 so I'll still be way ahead if I have Tesla reset the warnings. Most importantly I now know a lot more about my car then I did before the repair.

 

[KyleDay]

I will try that, although I did have both of those disconnected for a couple of hours on Sunday while replacing the heater. Does order in which it is done make a difference? Sunday I unhooked the 12v first and responder loop second. Also when you say "make sure to wait 5 min", do you mean I need to wait exactly 5 min, or at least 5 mins?
The service center said they would charge 30 minutes labor to clear the codes -- so $75.
BTW, I bought the 2018 battery heater on ebay for $55 so I'll still be way ahead if I have Tesla reset the warnings. Most importantly I now know a lot more about my car then I did before the repair.

At least 5 min.

 

[Palmtree]

At least 5 min.

Thanks. I'll give it a try and report back. I couldn't get an appointment with Tesla until March 4th so this will be most helpful if it works.

 

[Palmtree]

At least 5 min.

Okay. I disconnected the 12v and then the responders loop, waited about 15 minutes and bam! I'm good to go. Running like a champ. Thanks for suggesting. I never would have thought of doing another disconnect since it was disconnected the entire time I was working on it. I guess it needed one more restart after updating the new part with the 2020.48.37.1 software. No need to meet the ranger and pay to have him do this easy task. Thanks again. If anyone has questions about replacing the battery heater I can help. Total cost of $55. Actually I lost one of the bolts that holds the air cleaner housing. So it's really $55.55. I'm sure if your careful you can do it for $55.00 lol.

 

[KyleDay]

Okay. I disconnected the 12v and then the responders loop, waited about 15 minutes and bam! I'm good to go. Running like a champ. Thanks for suggesting. I never would have thought of doing another disconnect since it was disconnected the entire time I was working on it. I guess it needed one more restart after updating the new part with the 2020.48.37.1 software. No need to meet the ranger and pay to have him do this easy task. Thanks again. If anyone has questions about replacing the battery heater I can help. Total cost of $55. Actually I lost one of the bolts that holds the air cleaner housing. So it's really $55.55. I'm sure if your careful you can do it for $55.00 lol.

It’s $55.55 plus the Butterfinger you owe me for the great advice . Jk. Told you it’d work

 

[KyleDay]

It’s $55.55 plus the Butterfinger you owe me for the great advice . Jk. Told you it’d work

And to be clear - one more restart wouldn’t have solved it. HV error codes only clear after several minutes of power down and reboot (after the underlying problem has first been resolved).

 

[Palmtree]

King-size butterfinger

 

[EZBoy]

Congrats! You have fixed your Tesla without access to Toolbox good we now know a fully working procedure , too bad it has to be timed with software updates to work

 

[BigTonyTones]

How long it take you to do the installation? Im reading the service manual to get an idea and it doesnt seem very fun

 

[random155]

Congrats! You have fixed your Tesla without access to Toolbox good we now know a fully working procedure , too bad it has to be timed with software updates to work

I would hope that Tesla would remotely redeploy software if you request.

 

[Plasmid_Boy]

I would hope that Tesla would remotely redeploy software if you request.

My SC offered to remote redeploy for free after I bought a window control module from them.

 

[Palmtree]

How long it take you to do the installation? Im reading the service manual to get an idea and it doesnt seem very fun

I'd say it took around 3 hours total (less time if you are familiar with removing the frunk trim and other stuff under there -- it was my first time). You do have to remove quite a few things to access it. I'm 6' 1" and it was quite a difficult reach to unplug the battery heater from the junction box. I clamped the hoses and then stuffed wine bottle corks in them as soon as I freed them from the heater -- probably didn't lose more than a tablespoon of coolant (that was one of my biggest worries going in). Be careful removing the wiper arms. They are very close to the windshield glass. Don't do any prying in that area. I'm happy to answer any other questions while it's still fresh in my mind.