acarapella

Hey all,

This is a new one... I was told today by my family member's Lexus service advisor that she should get a new battery. its a 24f and no big deal, but he said there us a $48 charge to reinitialize the HVAC servo... I thought of having to cycle my sunroof on my ES, but this apparently requires techstream (which wouldn't necessarily stop me from doing it) but I wanted to ask on here before trying to make this all happen. I get brand new Interstate batteries for 1/6th of what this bill is, but I dont want to mess with her car if its more than a straight forward process. Please let me know =)

Its a 2015

Thanks

Drew

salimshah

There are techniques to keep +12 v supplied while the battery is replaced and personally I can [with preparation] swap the batteries in less than 30 sec without 12v.

Worse if you loose ALL settings, the relearning can be done with very little aggravation.

Check the owners manual about all settings and you can see which needs to be reset/reprogrammed.

In summary, you will be paying for convenience.

Salim

acarapella

Thank you!

You’ve peaked my interest... 1) what are these techniques? Jumper cables to the upper part of the terminals? I’ve heard of feeding 12v through the cig lighter with the car on “on” but not experimenting with this car

2) 30 seconds... if I can swap the batteries that fast, all is well?

still I wonder if this is an easy thing with techstream?

mandyfig

A Battery Tender plugged into your cigarette lighter will preserve your settings while you change the battery. Good luck.

Clutchless

Read post 11 on this link and pasted below. I explain how to swap out your battery with the power disconnected for only 30 seconds so you do not lose any settings.


You can do it yourself. You cannot damage anything unless you manage to put the negative cable on the positive terminal etc.

Red = Positive terminal and Black = Negative terminal.

OR many of the large chain auto parts stores that sell batteries in the US will provide you with a free installation in the parking lot when you buy the battery. I am sure it is probably the same in Canada.

If you replace it yourself, just work fast on the part where you pull out the old battery and put the new one in and re-connect the cables. If you can do this in under a minute or two, you will not lose any settings.
The trick is to first disconnect and remove the battery hold down piece. Then loosen the cables but don't remove them until both cables are loose, then remove the cables and then the battery and put it on the ground then grab your new battery and place it in the car and slide the cables on the terminals. Then you can take your time installing the hold down piece and tightening the cables.

https://www.clublexus.com/forums/rx-3rd-gen-2010-2015/903689-reset-after-battery-replacement.ht

Randyp1234

I guess I got lucky. I had to replace some battery cable ends and then later replace the battery and other than re-setting the windows I didn't have to do anything else either time. And even then not all the windows. In fact, I think when I did the battery I didn't have to do anything.

acarapella

Well shoot. Doesn’t sound too bad. If it was my car I wouldn’t car but being it my family members, I’d rather she not see any changes. Thanks all

salimshah

Loosing the settings is a disclaimer as it 'can' happen.

The other thing about quick swap is making sure the new battery is the right battery (with the terminals on the exact side/size/polarity). Ready jumper cables can be the backup plan.

Salim

acarapella

24f I am sure but I’d double check. The jumper thing makes sense for sure. I wonder if it makes sense to put them on before disconnecting the old battery and keeping them on until after the new one is in

salimshah

Well it all depends upon how bad is the old battery. Theoretically lead acid batteries should produce matching 12.xx volts and if there is a difference then the higher voltage battery would dump current into the weaker battery [principle of jump start]. If there is a cell short then the 2v difference with low resistance can mean lot of Amps. You can test out how much sparks fly when you connect the two batteries in parallel.

You are overthinking the issue. The vehicle is not going to fall apart if you have the battery removed for 2 hrs or even 24 hrs. Few settings will be lost (minor inconvenience) and the ecu would erase old driving habits and start re-learning [I chalk this up as blessing].

Incidentally, it is recommended to disconnect the battery before working on the vehicle ,,, so it is not an uncommon situation to remove 12v for extended time.

Salim
ps: The small battery tender [through the cig lighter] has limited current capability so it works out to be safer. The only down size is that the cig lighter is switched in Lexus and for the thing to work you would be turning the ignition on. The huge down side is if you disconnect the battery back-up with the ignition ON, it may mess up things royally [per my understanding .. this is an accident scenario... service manual states to turn the ignition off and pull the keys out and let the vehicle sit for few minutes before disconnecting the battery.]

Lexipro

I just swapped out my battery with no issues. $90 from Costco. Don’t overthink it.

acarapella

Thank you all so much. Normally, I would certainly not toil over something so simple, but this is in my car. It’s a family members. They know me as the guy who “build his own cars“ so they think I can do anything and nothing ever goes wrong. It’s nice to be somebody superhero, but I don’t wanna let anyone down either Haha

In Rochester, we are blessed to have an interstate battery distribution center. Any battery that doesn’t look 100% shiny and perfect is sold, with its cold cranking amps written right on it, for $48. Love it