T-SB-0054-24 how to you check to see that the ECU has been updated? Toyota dealer claims that the update has been completed, yet this morning after a full traction battery charge the 12 volt battery indicates 12.2 volts and recommends it needs to be recharged.
Usually a TSB that calls for a firmware update will show the revision number (they usually call it a "calibration ID") that the ECU should be updated to. So you connect with Techstream or another scan tool that shows your ECUs' calibration IDs, and you see if it's now the one specified in the TSB.
without knowing the condition of the battery prior to the tsb being performed, they very well could have. it won't fix a damaged battery. if it fails, they will replace under warranty. it wouldn't hurt to give it a full charge and then check it regularly
this is the second 12 volt battery under warrant. the replacement battery has 470 cca and is 3 months old. interesting observation by me is when the traction battery begins to charge, the 12 volt battery shows 14 volts when checked with a volt meter...the toyota mechanic at the dealer said that the traction battery charge cable does not charge the 12 volt battery. who am i to argue? i must be hallucinating.
The 12V battery is ONLY receiving a charge while the traction battery is charging. If the traction battery isn't charging the 12V battery isn't charging; just because it's plugged in. At least that's how it works on the gen4. That's why the OM states to disconnect the charging cable when traction battery charging is complete. While charging cable is connected to the car, the car is doing more frequent diagnostic checks using the 12V battery ONLY and drawing it down... FWIW: I'm still on my original OEM battery...
What about leaving the car in "Room Mode"? I am pretty sure that when the car is in room mode it charges the 12V battery while not charging the traction battery. In my experience I can leave the car plugged when the traction battery is low and now have to worry about unplugging the EVSE to maintain charge in the 12V battery. A couple of little details if you don't want to waste unnecessary electricity is that you have to turn the display off, the climate system, automatic headlights and unplug anything plugged into Power outlet (12 VDC) or USB ports. You also have to use the physical key to lock and unlock the car while in "room mode."
Don't have room mode on a gen4; so can't speak for that function. Would that be similar to leaving your car ON and walking away from it? Why would you have to unplug all your power outlets or USB ports if the DC-DC converter is ON - seem more trouble than it worth and your leaving your car ON while trying to charge while your not there??? Tiny home for homeless people????
similar - yes. the same- no You can't drive the car without the fob to start it. The doors are locked. I guess if someone broke in they could turn on climate, charge their phone, listen to music, turn on the lights. That is about as much I have been able to get to work when in room mode.
Thanks for the clarification. I guess the question is; why go through all the trouble of leaving the car in 'room' mode and having to use the manual key to lock and unlock it? Doesn't that kinda defeat the purpose and convenience of the FOB? Is it because they're too cheap to replace the dying or dead 12VDC battery??? Sorry; I just don't get it.....
Room mode is for allowing you sit in the car with AC on while it is charging. Maybe also for car camping. Something other plug ins allow, that Toyotas weren't until now. It's just a work around for charging the 12V.
