Evanner

I have an 03 IS300 and after changing my battery my car all of a sudden wont start.(Coincidence?) I have already put in new alternator (due to over charging), plugs, wires, coils and valve gaskets. The plugs were soaked in oil which I thought was the issue but still wont start. Car will turn over but horn and radio wont work. Already checked all fuses and are in good working order. THOUGHTS?!!?

Lexusdk

You should perform a voltage drop test. Its possible that there is a bad connection somewhere. Check you battery terminals and post. Then check the ground cable to the chassis for any corrosion build up. If there is any, clean it off with some sand paper and try starting again

ISBeast300

when you unlock it, and put your key in the ignition, look at the dash- is the "security" light still flashing or is it off?

if it is still flashing then your car has gone into lock out mode