Batter or alternator??

Your elternator is bad you need to replace new one

I am not sure if I have the belt on the engine that drives the alternator. My car is a 2006 Lexus GS300 with 220,000miles. I have never changed the serpentine belt. I guess I will change the it and see if that resolves the problem (fingers crossed). The belt is due for a change anyhow, after all those miles. If it isn't the belt then what do you recommend I should do next?

Did You change the ECU? If you did and didn’t reprogram (See the new ECU or Computer Same Thing) are VIN Vehicle Identification Number Specific to the Computer,So when you put in a Computer from a Different Car the VIN Doesn’t Match So the Anti-Theft Kicks in and That acts Like the Battery is Dead ,Won’t Start,That is one of the main reprogram things the Dealer does for $2000,Copy Your VIN from the Windshield to the New Computer with a keyboard WOW.You Can have anyone who can use a couple Wrenches and Read Change this and Reset it,go to Justanswer.com you donate whatever you feel it’s worth,tell them you want to replace and reprogram the ECU on your 06 Lexus GS and they will walk you or Whoever will Change it through it a heck of a lot cheaper then the Dealer,Never go to the Dealer unless you have a Free Recall or are under Warranty!

My battery on my 2006 Lexus GS 300 went dead. So, my father recharged it. I went around the block and it ran like normal. However, when I turned it off. The battery went dead again. So, my father recharged it again and I rode it around the block again. It had good speed and ran like it should. However, again , ithe battery died when we tried to crank it. This time, he put water in the battery and charged it. My car cranked but it would not go no faster than 10 - 20 miles per hour this time around. Then, I managed to get it to the dealership. They want to charge me $1212.00 to repair the ECTs throttle control, intake manifold gaskets are leaking now. Replace the bittle vacuum lines, spark plugs, engine air filter, irepair or replace the intake hoses that are dry rotted and cracked and repair the VVTI oil hose. Do you know if the price for this is a good price or am I being over charged for this work? Is all of this necessary to get my car back operational?

OK ..did you see any check engine light on your dash..if it does then go to autozone to check that for free ...because the dealership want replace all this part maybe it's not necessary ..and maybe not solve the problem. .so my advice scan the vehicle and tell me what you get...thank you...

your alternator is bad

Lexus vehicles have a history of “parasitic slow drain” on the battery. My wife’s 2006 Lexus GS300 has the issue and it’s in the shop now to determine what’s draining the battery. After putting in 4 new batteries, we finally learned about the “slow drain”. As I understand, Lexus are notorious for this issue. Since my wife doesn’t drive the Lexus very often and it has low mileage, we learned Lexus are made to be driven, and not sit in the garage for days, or weeks without being driven. Various modules draw on the battery even when the car is not in use. We consider this a manufacturer defect.

I bought my wife a 2006 Lexus GS300 in 2008. That was before she retired and we moved to Idaho. As long as she drove the car to her daughter's home, only a mile away, to baby sit the two granddaughters, the car performed without incident. However, after she stopped driving the car everyday, and sat in the garage for 2 or more days, there was a consistent parasitic battery drain. Called our emergency road service and after jump starting the car, I'd drive it for about 20 minutes then return to the garage and as soon as i turned the engine off, and tried to restart it, it wouldn't start. This has been an ongoing issue since 2016... and the car has only about 57k miles on it. I let the car sit over the winter, but as soon as April 2020 came around, I had the car towed to a independent Lexus/Toyota/Suburu repair shop... NOT the dealer. After troubleshooting the various things that may draw off the battery and letting it slow charge overnight, it still has a parasitic slow drain pulling off the battery. The co-owner of the garage/shop said "Lexus are made to be driven" and suggested I buy a slow charging device and keep the car battery hooked up to it over night, if not all the time until my wife wants to drive it. So, I bout a digital slow charger from Costco... cost about $39. That seemed to keep the batter charged up but to me it is a manufacturer defect that a continual battery drain is a big headache. By the way, I bougt a new battery, and under warranty, replaced it three times. The last time the source told me that was the last free battery they'd give me.