2011 Lx570 charging issue help

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Joined
Apr 25, 2010
Threads
8
Messages
45
Location
South Texas
My wife's Lx has been basically trouble free besides a water pump at 110k miles until a few days ago. It now has 115k miles.
She went to start it and the battery was dead. I jumped it, then took it to have the battery tested. Two auto parts stores tested it (possibly a mistake) and said the 3 year old battery was strong but the alternator showed only around 13 volts and is going out. After realizing replacing the alternator isn't as easy as my '86 Chevy was, I took it to a trusted mechanic who specializes only in foreign cars.

They replaced it with a new Denso unit.

Yesterday after picking it up and driving on a 3 hour trip the dash lit up like Christmas: CEL, VSC, 4Lo, among other lights. Then the voltage dropped until it died. I figured it must be the battery after all and replaced it. Made it the last hour and a half of the trip no problem.

Today, my wife was driving and the dash lit up again, but this time the voltage was climbing. She said it got almost to 19v on the dash gauge. She made it home thankfully.

I generally try and do all the maintenance myself and have so far on this and my 100 series, but this has me frustrated and stumped. Has anyone here experienced anything like this or can point me in the right direction?

I'd like to get it back to the same mechanic so they can make it right, but he's 3 hours from my home. It might end up at the Toyota dealer as that's as close to Lexus as we have here.

Thank you and sorry for the wordy post.
 
Thank you.

It's draining the battery very quickly after just sitting without running so it's headed back to the shop. I'll try and update this in case anyone else has similar issues.
 
When you had the new alternator put in, they probably swapped over or replaced the voltage regulator. Charging at 19V sounds like a voltage regulator issue to me...maybe not installed properly (I think a bad ground can cause an overcharge?). If it was overcharging for a period of time, that's not good news for the battery.
 
So the vehicle is fixed and thank you all for the replies.

The battery that was in it turned out to be bad according to the mechanic. He said it would charge to start but only surface charge as he calls it. So the alternator was having to work overtime to keep the truck running and fried its internals causing the regulator/ sensors to fail, hence the under and over charging.

He said once the internals fail, it can draw amps even with the engine off, explaining the dead battery after sitting overnight.

Thankfully he was able to get another new alternator under warranty, and he covered all diagnostics and labor under his warranty. With the new battery fully charged and alternator everything works as it should.
 
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