bill444

The battery terminals were corroded on the RX350 I just bought. I cleaned them up and everything started up normally and then again started 30 minutes later when I left to get gas. When I pushed the start button after getting gas, nothing.

I eventually found a thread here where someone suggested holding the key fob directly against the start button and that worked. I guess there must be some kind of passive RFID tag in the fob. After driving home, this seems to be the only way to start the car. I tried my second key fob and it also only works when held against the start button. No traditional push button start.

Battery is about a year old from Lexus. 12.4V. With the engine running the voltage is above 13V as expected.

Any ideas?

I do have some key fob batteries on order and I guess I will change them but it seems the odds of both going dead at this specific time must be slim.

Non

So does the door lock still work with the key fob?

First thing to do is get new key fob batteries, but you can check the key fob battery voltage, and if it's 3 volts or higher then the battery is still good.

Last time I changed my key fob battery, it was at 2.7 volts but still worked fine.

bill444

Yes the door look still works with the key fob. I will check the fob battery voltage.

I am wondering if they remote key system has its own fuse and maybe it blew. I will look that up.

Thanks

bill444

2.95V on the old battery. I went ahead and changed it but no difference. No messages about the key fob batteries or anything similar.

Edit: Not sure if these were the right fuses but found two IGN 30A fuses in the engine compartment and they tested good. The car still starts up fine if I hold the key against it the button.

darkstorm8

wow thats so odd... so the only way to start your car is by holding the keyfob up to the start engine button and the keyfob battery is newly replaced? and the keyfob works to unlock, lock, open trunk, honk horn, and if press the unlock button and keep holding near to but outside of the car it will open all of your windows and sunroof just fine?

Clutchless

You may need to have a locksmith or dealer re-program your key fobs. I would also try some searching across this entire site as the fob and start button are shared by all models and someone else must have had this problem before you did.

Non

But, do you press the key fob button to unlock the doors? Or do you touch the door handle to lock/unlock while the key is in your pocket?

Another question, when you press the start button without touching it with the key, does the info screen say "Key not detected" ? or is everything silent?

I'm asking because the "Smart Access" function can be disabled in the customization menu, page 838 of the manual:

Non

bill444

So, the door lock functions on the key fob were working correctly and it was just the push to start that was not working. Never had an error on the dash about the fob batteries.

I went through all of the Lexus Customization settings and it turns out push to start was disabled among a few other settings that were different after disconnecting/re-connecting the battery. Just like Non's picture.

Push to start does not appear to be disabled by default so I don't know what to make of these settings changing after disconnecting power for 5-10 minutes. The Lexus dealer I bought this from a few days ago reset the customizations with their scan tool before I took delivery and they believe the car reset back to previously stored customizations when I disconnected the battery. They can't find anything wrong with electrical system per the service history or any stored codes but only time will tell.

I spent an hour or so searching the archives here and never found an exact match. The biggest problem was I did not understand push to start could be disabled in the first place and did not realize there was a proximity reading technology built into the fob as a backup start trigger.

I appreciate everyone's help here.

salimshah

We learn something new by others sharing their experience.

Thanks

Salim