I’d like to preface this by mentioning that the car I’m dealing with is a 2006 Toyota Crown Athlete, but I’m posting under the IS350 category since they’re essentially the same platform.



The issue began when the battery light came on, which led me to replace the alternator with an OEM part. After connecting everything as usual, the car now refuses to recognize the key. For reference, the key fob battery was recently changed, and it works perfectly fine. I’ve also ruled out the car battery as an issue because I’ve switched between multiple batteries and she's still unresponsive.



Also most of the interior electronics are non-functional. I can’t adjust the seats, open the fuel cap, or activate accessories. The only interior features that work are the lights and turn signals. Accessories like power seats (don't require ignition) are completely unresponsive, and the car won’t switch to ACC mode.



I’ve already checked all the fuses, and they’re in working order. She's taking the **** out of me at this point man I just need some advice to what might be causing this.

 

Did you check the fusible link? Typically blows when people mix up the positive and negative terminals when replacing the battery.

 

This. Also, perhaps you can find more ideas here: https://www.clublexus.com/forums/is-...t-working.html

That being said I have a feeling this happened to me after alternator replacement (car wasn't started for 2 weeks). I think I just did the "dead key battery procedure" and that fixed it . Basically, turn everything off, exit the car and locking it with physical key. Then unlock it again. Get in the seat, and try starting it by holding the key over the Engine Start button. There's the video here . Good luck...