demark1

Having some serious issue tonight. Son started driving my 2005 LS with the valet key (he is new driver, we had 3rd key). Battery dies tonight supposedly. He gets a jump from friend and drives home, turning off car again in my driveway. I restart it to drive around a while on highway to recharge, figuring I will get a new battery tomorrow (it is 2-3 years old and I feel lucky it started up.... Battery sudden death is no surprise on this car and battery is old enough not to try to save.).

I pull into driveway and turn off car and thinking to save battery charge overnight, I turn off the keyless start by pressing button under dash --, I have done that before when I am away for a while. Then on a whim I try to start car and it turns over (without starting) WITHOUT INSERTNG KEY! What the heck? I take key WAY out of car and it still does this. Reenable keyless start and I press ignition switch in and see "key not detected" (correct) but it turns! seems to not start (suspect there is a fuel cutoff separate from key lock of ignition switch).

Car started at one point too with a horrible post-start grind momentarily. I am actually not sure what the mode was (keyless on or off, was key in the switch when I turned it etc.)

I am thinking the ignition TURNER (interlock?) is broken, or a flakey battery has totally messed with ignition switch electronics and/or starter. I am, also worried car might start without a key. I THINK it turned over but did not start without the key, but I am not sure. I was afraid to test more in case I overheated the starter. My son said when it failed to start that it was a fast clicking, which makes me think the original issue was the battery rather than an ignition key interlock issue...

I am not expecting an answer here, but just wondering if I should start with just getting a new battery or simply scheduling an appointment at a dealer. I hope, hope that there is no starter damage. I guess a new battery is cheapest but hope the car does not need major repairs. That grinding sound did not sound good the last time the car started.

I know that weak battery or bad cells can play havoc, but the ignition turning with no key in the area did freak me out. There could be more than one thing wrong here... has anyone experienced the ignition switch turning with no key in the car?

Just sharing, thanks for reading, any advice welcome!

demark1

Update: I got brave and tried turning on car. It started fairly normally. I think it is the ignition switch lock mechanism that is faulty. Not sure if that could be causing a drain on battery (some solenoid getting powered) or if the two issues are unrelated.

BigBoomer

Most likely caused by the low battery. These cars behave very strangely with a low/duff battery.
The ignition switch probably held it's state after you turned it off and thus allowed you to restart even without the key.
I'll bet if you disconnected the battery, waited a few mins, then reconnected it, it would not allow you to start without the key.
Get a new battery installed, check that the alternator is charging correctly, check that you don't have a parasitic drain,... and forget about it. :-)