Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.

Running Service Mode Coolant Drain/Fill or Thermal Drain/Fill Options Not Working

This site may earn commission on affiliate links.

I recently removed and replaced my 2018 Model 3’s radiator, and in attempting to follow the service manual procedure, tried to use the service mode>thermal actions> ”start thermal fill/drain” as well as “start coolant fill/drain. Both of them gave errors that “they could not run, and to check that another thermal test was not in progress” (it wasn’t) so if I then ran the “Test Thermal Performance“, it would run and complete the test successfully- I could then run the fill/drain options, however it says when you start them that they will run for 50 minutes, but within about 5-10 seconds they switch from “running” to “routine passed” and the coolant system status quickly switches from “not ready for fill/drain” to “ready” then right back to not ready.

I ended up just running the vacuum coolant filler while doing a couple of thermal tests, and seem to have gotten the air out of the system, but the thermal test only lasts about 30 seconds, so I’m not able to pull a vacuum on the system for the full 3min, 2 times as instructed in the service manual.

Does anyone know if this is the correct and expected operation of these functions, or am I missing something? The service manual says the coolant system status may be “not ready” if the drive rails are energized, and to de-energize the drive rails to complete it, but doesn’t seem to explain *how* to de-energize the drive rails. It warns of pressing the brake to start the car, but you have to unlock the gateway to start the fill/drain modes, which involves putting your foot on the brake and energizing the rails (I think)?

Thanks in Advance!
  • Informative
Reactions: KenC
Have you done a hard reboot, then run vacuum test?
I ended up just doing a fairly thorough vacuum fill and then supercharging and checking the level during the process when the pumps were running at 100%..

I talked to a SC tech later who claims that when you start the drain/fill procedure in service mode, it runs for like 30 min in the background, but that doesn't really make sense with what it's showing on the screen. Either way, seems fine. TL;DR- do a solid vacuum fill and then Supercharge and you'll be fine.
  • Like
Reactions: shahryaran