So I bought a used 07' Is350 about 3 weeks ago. A week after I got it I got a check engine light and my code reader was reading for 2 transmission codes. 1-transmission slipping and 2-bad solenoid. I wasnt too happy since I just bought the car and figured the previous owner probably cleared the codes then sold it to me. I checked with a couple of friends in the auto mechanic industry and they said to just replace the tranny.
Yesterday the guages starts bouncing all over the place and the nav screens keeps going off and on along with no power steering. I check the battery with a volt meter and its reading 8 volts so I put in another battery that I had and it fired right up like it wouldnt with the other 1 when I turned it off. So after putting in a new battery it was fine for about a day then the same thing, guages bouncing and no power steering. Today I put in a new alternator with lifetime warranty and its reading 13.5v or so we will see how it goes. I drove it around for a 1/2 hr with no problems.
Im really hoping that the engine lights were caused by the alternator failing and I wont get anymore codes. Im keeping my fingers crossed. I know that with these modern cars, electrical issues can cause havoc.

 

It is quite possible that your bad alternator and weak battery caused the issue. Some weird stuff can happen when the battery and alternator start going. I have seen cars that have almost caught on fire from the cats glowing so red hot that the carpet started to smoke. All because of a bad battery, not enough voltage, lack of spark and raw gasoline pouring into the cats.

Let us know how it goes.

 

I agree with the above. Bad batteries and alternators can cause all kinds of weird things on cars these days