I'm a new owner of a used Lexus SC430 and very happy. Got it from a very reliable dealer. After a couple months of regular driving the warning light with a battery came on. I looked it up and saw it noted a possible belt problem with the alternator. Before I got to it the next day the audio system and a handful of other items including the headlights went on the blink. I got home that late evening and when I checked it the next morning, all was fine and no warning lights. That was 3 days ago. I'm still concerned. Any ideas or suggestions?

 

I guess no belt is broken?

you could take it to autozone or equivalent and ask them to check for any stored codes.

i suppose it is possible the alternator is going bad.

BTW, Welcome to Club Lexus, post a pic of your car to share with us.

 

I would check to see if your battery clamps are tight. See if you can wiggle them. If you can, tighten them down or get Battery Shims.
It is possible your alternator is charging properly, but your battery is not receiving because the clamps aren't tight.

If they are tight then go to Autozone/Oreilly and ask them to test your alternator. They will do that for free. If it tests bad, then you have two indications you will need a new one soon.

Also, did you hear any kind of squealing noise when the light was on? Something to indicate your alternator wasn't turning properly?

 

I agree with both of the above but if you go to Autozone, have them also do a load test on your battery. If you saw the problems after not driving for a while, it is possible that a bad battery could have drained down. However, I suspect like DashingDar that you likely have a bad battery clamp connection. If there is all sorts of crud over the connections, you'll need to remove them and clean up both the clamps and the battery terminals. If the clamps look damaged or the wire connecting to the clamps look damaged, you'll want to replace them.

 

...first I would check the connections for corrosion & also being loose, these are the easiest & cheapest fix, if this is the issue. I'm leaning more towards the alternator because these were the same symptoms I encountered, when I replaced an alternator for a previous LS & my current Sc. A simple test would be to turn on the car & all the accessories (radio,lights, a/c, etc....) , then see if all the lights on the dash "pop on" after a few minutes, this is almost a sure sign that the alternator isn't charging properly or at all. Also, you could take the battery to Autozone, O'Reilly, etc....and have them load test it. I would do either of these without driving the vehicle, because if it is the alternator or battery, you wouldn't want to get stranded out on the road