I noticed that there's no DIY for changing the battery. Maybe it's obvious to most people, but this was my first time and I noticed some things that were different with the IS250.

Tools:
- 10mm socket wrench
- 10mm or variable crescent wrench
- flat-head screwdriver (for prying)

Some notes:
- I had my battery for 91,405 miles, almost 4 years (3 years, 361 days, to be exact). I changed it because it failed the load test during the 90K.
- My dealership wanted to charge $185 for parts + installation.
- I bought the Optima Red Top #25 from Amazon for $138. I think Auto Zone sells it for $181. (Amazon currently shows it at $136.53.) Other batteries like the Die Hard Gold are cheaper ($99), but I wanted to get something that was of quality and had good reviews. The Die Hard Gold is their cheaper line; their top-of-the-line is $218!
- The Optima is smaller than the OEM Panasonic battery that comes with the car. The provided tray is needed to attach the clamp securely.
- The plastic surround doesn't work with the Optima, so I just put it aside.
- The radio doesn't need a security code (2006 IS250, no nav).
- The radio remembers its presets (manual says otherwise).
- Battery pads are available at auto part stores. They say that they prevent corrosion. The OEM battery had them, but I didn't install them on the Red Top because all the connections looked clean.
- Most auto parts stores like O'Reilly take back car batteries for free. If you take it back to where you bought it, they'll pay you for it (something like $12).

1. Disconnect the negative terminal with a 10mm socket wrench.
2. Disconnect the positive terminal with a 10mm socket wrench.
3. Unless you have a special socket wrench, you'll need a crescent wrench for the nut holding down the clamp. Remove that.
4. Remove the clamp bar.
5. Lexus has a plastic surrounding the battery. The two leads for the positive terminal are attached to this surround. In order to remove it, if you can get a screwdriver into that narrow space, there are two slots that it goes into to release the wires. I just pried it open.
6. Remove the plastic surround.
7. Remove battery.
8. Insert new battery.
9. Replace plastic surround and re-insert wires into clasps. (I couldn't do this step, so I just put the surround aside.)
10. Replace clamp bar, tighten clamp nut.
11. Reconnect positive terminal.
12. Reconnect negative terminal.
13. Start the car.
14. For each window on its door switch, roll down the window half way. Roll up until you see the switch light stop blinking. The window's auto up/down has been reprogrammed.

Optional:
Turning off the seat belt alarm - https://www.clublexus.com/forums/1588110-post28.html

I hope this helps people who might be confused on how to get it done. The annoying plastic surround kept me busy for about 20 mins! Otherwise, the battery change should have been a 10-15 min job.

 

changed my battery yesterday. Piece of cake

 

Awesome write up. I was planning on changing mine in the next few months too! Thanks!

 

Ha! Around the same time for another 06? Must be some kill switch on the batteries to make us spend more money

 

thanks for the detailed write up!

 

Nice job on the write up

 

Thanks for the props, guys. I'm always looking up stuff done by other CL members, so I thought I'd give some back (this is my second DIY post).

Can a moderator add it to the DIY page?

 

good write up. its the same as the GS and i just changed my battery last week. Have to say that plastic cover around the battery was a pita to get off lol.

 

Hah, I remember when I first bought my car and I tried to take it for a test drive but it wouldn't start up. The battery just happened to die at that very instant. The sales associate was a little embarrassed.

 

great DIY! thanks mikeho!

 

Just replaced my battery with a redtop last week.
Awesome improvement.

 

How long is the factory battery expected to last? I've never changed mine on my 08 350.

 

i replaced my battery not cuz i it needed to but cuz i wanted to

 

Most batteries last 3-7 years depending on usage. If your battery starts to fail, the first thing to check is to see if corrosion is dirtying the connectors. If so, clean them and your battery most likely is fine.

I drove my car pretty much every day (save for vacations). So that would be at least 4 years and 300 days of driving.

 

Niceeee DIY! ...Damn battery's are expensive. you guys run Yellow tops?