I got a '08 LS460 that has been throwing random CEL codes for couple of months.

Two months ago it threw a P0012 (Cam Shaft Position 'A' timing over retarded). unplugged battery for 30mins and code went away. Couple of months later, I get a VSC warning with a check engine light for p2240 Oxygen sensor and a P1364 code. It was on for couple of days than went away on it's own. Car has 150k miles and no issues I noticed so far. Battery is almost two years old and Alternator is new. I'm thinking since unplugged battery cleared these codes, it could be electronic but I don't know much about Lexus cars.

 

It could be thep years old. The LS constantly drains the battery when shut off. Check battery voltage across posts before starting the car in the morning. You can then start car and read voltage. Report the voltages to us.

 

I will try that, I just took it to auto parts store to check the voltage and it passed but you mentioned checking before starting it in the morning so I will try that and report back

 

The electronics are known to be sensitive to low voltage. The symptom is lights and codes. It ‘s more likely to occur if the car sits for multiple days. A battery tender is useful in these circumstances.

 

Would you think a bigger battery would help with it draining it while sitting?

 

Starting batteries aren’t built to provide long term power. Deep cycle batteries aren’t meant to supply high starting current. Marine batteries are dual purpose, built to do both. I suppose one could try to find a marine battery with ample starting amps and put terminal adapters on it. If there is no electricity to plug in a maintenance charger…..I used to be a boat captain, that’s why I know about marine batteries.

 

The rule of thumb often given is, get the most powerful battery that physically will fit in your car. I'm not sure how you'd even determine that, even when I worked for a fleet and installed maybe a thousand batteries over the years, not once did I ever have occasion to measure one for size (BTW I checked every battery I installed for water level. And every one of those batteries needed topping up with dist water; I swear to you on every battery I ever installed the cells were low - EVERY. ONE.).
Also I'd clean the battery clamps like new, and I'd check the ground connection(s) as well for corrosion and tightness.

Anyway I have not had your problem with batteries on my 2017 LS 460 (yet) but on the sophisticated cars crammed with electronics that we own it seems ripe for them, especially if the car isn't driven every day. So I keep a trickle charger installed semi-permanently under the hood. I zip-tied the cables in place and I just run the power cord out through the grille. (I have to admit though I also made a reminder-sign for myself plus my significant other, to hang off the steering wheel, reminding the driver to unplug the charger).

My other car is a 2002 V6 Camry, and it has a solar charger panel sitting on the rear shelf. I run the cord for the gator clips under the rocker panel covers inside, and I just close the pass side door and hood over the cord. Been using that solar panel for 8 or 10 years now, it still shows 17 volts in daylight whenever I test it with the VOM meter.
If I had to park the Lexus outside again and couldn't plug in the charger, I think I'd invest in the most powerful solar panel I could find and hook that up instead; because I truly doubt the little shoe-box length panel that's in the Camry could do much good for charging on the Lexus!

 

I agree with Marcelo. A larger starting battery will give you a small amount of extra reserve, maybe an extra day?? But it’s more about cranking amps, for cold weather. Solar is a great idea if you can’t plug in a battery tender. I’d do that before trying to install a marine type battery.