clp71220

I want to say thanks to all who are contributing to this. It is greatly appreciated.

LEXUSC-400

When you are testing for a draw It is recommend to lock the vehicle. The car goes to "sleep" much faster. Also it is recommended to lock your vehicle when not in use since it shuts down most of the computers (some people that park in a garage may not lock the car). These are amazing vehicles, I'm sorry you are having this problem. I hope you can sort it out soon. It's a shot in the dark but check the seat switches, I've had a few different customers where a seat switch was causing a draw on the battery.

Johnhav430

I don't think our cars are sophisticated enough (being 2001-2006), but I thought someone said our cars don't like AGM. I do know that in my BMW, if one goes from lead acid to AGM, the car needs to be coded and programmed. If a lead acid is replaced with a lead acid, then the car needs programming. The programming tells the DME that it has a new battery--if it is not told, it will charge the new battery as if it is x years old (however old or however long since the last programming took place). If our cars are not sophisticated like BMW, which I don't think they are, then the key imho is matching up the CCAs first, and hopefully the RC is comparable. but I'd be curious why someone said our cars don't like AGM....

sha4000

iTrader: (1)

Shouldn't he just check EACH and EVERY fuse if he really wants to find what's drawing power with the car off?

GrahamG

If we are to access the fuse boxes in the engine compartment after locking the car and waiting for it to sleep, will it not be necessary to fool the car into thinking the hood is closed?
Perhaps there is a micro switch that needs to be held closed.
Presumably checking current draw across the fuses inside the cabin will not be so easy if the alarm includes a movement sensor?

My '04 LS430 with new good quality battery failed to start the engine after 12 days [not completely dead] but it is good for say 6 days. Next time I will switch off the smart key system with the button on the dash but that should account for so much discharge.

Thanks for any contributions to this problem.

tallcaguy

My 04 ML w/ 3+ year old battery started right up after sitting for 8 days.

nedear168

Are there documentation that AGM battery not compatible to our LS?? AGM vs Lead acid type batteries is different material to keep battery charge, any car alternator HAVE voltage regulator to determine when it needs charge or not, whatever it is...I drove my LS to work and it's never been this smooth, quiet and peppy since I bought it a year ago, also...the idle speed is much much more stable, may be it's just my imagination!!!

clp71220

I have been working nights since my last post. I will get off this coming Thursday so ill be able to pick this back up. GrahamG sounds like your having a similar problem. I am driving the ls 430 every day and checking the battery before I use the car. In a 9 to 12 hour period the battery drops from 12.4+ to 12.2 volts. Looking forward to the find.

clp71220

Well i pulled all the fuses with no change to the amp draw. I am now looking at the alternator. Ill have to get the car picked up to disconnect the wire from the alternator and see if that is it.

Johnhav430

I wonder if there's a methodology to checking fusible links....

Here is a thread regarding being unable to turn the wheel i.e. some sort of electrical issue....

https://www.clublexus.com/forums/ls-...ekey-turn.html

LS430Lexus

AGM batteries work fine in these cars. I have used them in my LS's ('97 LS400, '02 LS430UL, and '03 LS430 Nav/ML) with no issues.

clp71220

Well sorry for the delay on this post. I had the alternator tested at an auto parts store and they said it checked fine on the tester they where using. However i was still not convinced that my alternator was fine. So i bit the bullet and had the Toyota dealership do a diagnostic check at $120 on the car for a parasitic battery drain. I said nothing about the alternator as i wanted to see what they would come up with. I was not there 15 minutes and they came back and said i needed to get a flooded cell battery before they could run the test. I guess they had a problem with the optima red top battery. So i agreed to return later with a flooded cell battery. I swapped battery's with my other car and returned and had them run the test and the Alternator failed the test and said it had a abnormal ripple. I guess this means that one of the diodes must be going bad or is bad. They wanted $900+ to replace the alternator and i have elected to do it myself. Due to work lately i have not had a chance to swap it out. But i will post back when i get this done and let you know if this fixed the battery drain.

Arcturus

Good work. It's pretty easy to change out the alternator on that car. I dunno why the dealerships mark up the prices so heavily. I think you can get a good alternator off Rock Auto for like $200 dollars.

clp71220

Hello everyone. I got the alternator swapped out and so far so good. The charge rate is up to 14.2volts verses 13.6 volts and the parasitic drain is now at .15v to .30 volts probably the security system. I wanted to say thanks to all of you that helped with your post. I pray that God will Bless you all. Thanks