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The battery dies all the time now on the 2006 LS430. Something is draining the battery. The Mark Levison amplifier seems to be the issue. Any fixes or just disconnect forever???
How often do you start and drive the car? Every day? 1x a week? Every 3 weeks? How did you determine the audio system is the culprit?
I've read and learned on this forum that the Smart Access uses a significant amount of battery to the point where you MIGHT end up with a dead battery if you don't drive the car at least 1x every 2 weeks! I found out the hard way! I have a company supplied truck and also a second personal vehicle, so there was a period in time several months ago when I didn't drive the LS for several weeks, and boom, I had a dead battery! It was less than a year old battery too.
If you don't drive the car at least 1x a week, you might want to consider shutting off the smart access function. It's a button under the dash, above your right knee when sitting in the driver's seat. There are 2 buttons next to each other above your right knee. The other button is for the TPMS initialize. I don't know off the top of my head if the left button is for the smart access or the right one.
If you don't drive the car at least 1x every 2 weeks, try shutting off the smart access to see if that is your battery drain.
Have you diagnosed the source of the drain? when power is off, the stereo/amp is off, and I believe is not powered.
Are you sure so?
Toyota requests amplifier companies not to get the full power from the ACC line. There are amplifiers and some other units that need big current and Toyota's way is to get the big power from the battery directly through a fuse. But there are devices that control the power consumption from the battery. Some use semiconductor switches and some others old fashioned relays. When the power control circuit fails, there happens the draining current.
The main power amplifies are directly connected to the battery through a fuse and you can check the draining current there. I don't have a ML's circuit diagram but this is an example of a Pioneer's amplifier CRT3108 for LS430. As you see, +B (CN803 Pin# 12)is always supplied to circuits. ML's amplifier must be something similar, I bet.
Last edited by Yamae; Aug 3, 2025 at 06:51 PM.
Reason: To add an example.
Toyota requests amplifier companies not to get the full power from the ACC line. There are amplifiers and some other units that need big current and Toyota's way is to get the big power from the battery directly through a fuse. But there are devices that control the power consumption from the battery. Some use semiconductor switches and some others old fashioned relays. When the power control circuit fails, there happens the draining current.
The main power amplifies are directly connected to the battery through a fuse and you can check the draining current there. I don't have a ML's circuit diagram but this is an example of a Pioneer's amplifier CRT3108 for LS430. As you see, +B (CN803 Pin# 12)is always supplied to circuits. ML's amplifier must be something similar, I bet.
No, my answer was non-technical. I just figured the power seems off when the car is. But that was my larger point: "When the power control circuit fails, there happens the draining current.". Perhaps the control circuit is bad rather than the amp. Do you really want to cut out the amp if it might need a relay, etc.? I'm just suggesting not to guess.
could just be a bad battery... have the battery and charging system tested, followed by proper current draw diagnosis.
I have had my car over 16 years. At least 3 times where battery suddenly died, sometimes after restarting car after a 1/2 hour trip. Whether battery is bad or discharged, I do not trust a battery a day over 3 years old on this car. Given mostly short trips now (vs a work commuter car in past when my wife drove it 30 miles daly), I tend to turn off the smartkey functionality as well.
I also had weak battery affect tilt motor auto-retract when I still had that on.
Not saying that is issue here with the original post, but a weak battery can cause problems and sudden no-start out of nowhere.
