posts here.
1. When I bought the car I have one key w/ remote, then I bought a pre-cut and a used key using its remote, programmed myseflf follow service manual, both work well
2. now I bought one precut from ebay, marked DENSO has Lexus logo, quality ok, cut is slight offset, I can only insert half of it into my door.
3. Program failed, confirmation mode shows I have two keys already registered, but add mode has no reponse - as a few reported in forum - I guess remote chip may be different

my questionL
1. does a well cut key w/o remote/chip can start the car?
2. which chip version, or legal Lexus part number is for 05 GS300 key w/ remote?
3. It looks like 2nd V6 Lexus still use multiple different key? who knows this?
4. Internet shows type 1/2, 4C/4D chip, which one is for 05 GS300?
many thanks, I plan to ask ebay refund and needs your help!

what does transponder key mean? with chip inside but no button?

more: I looked at existing key (not sure it is the one came with the car or the one I duplicated), it is
HYQ12BBK canada 16511032233
I googled the HQY12BBK is used for:
2003 2004 2005 2006 ES330
2002 2003 2004 2005 2006 SC430
2001 2002 2003 2004 2005 2006 LS430
now I'm confused which key would work for my 05 GS300. Forum says LS430 is not programmable by user.

 

lastguy,

Ask for refund, is obvious of that key is not for your car?

You say this in post here #2. cut is slight offset, I can only insert half of it into my door. It teaches you that key is NOT for your car.

 

Thanks. Retry shows it is accepted by the car, the problem is I added it two times into the car, now the car has four keys registered(max).
Unfortunately the key cannot start the car! Summary: remote can open side doors and trunk, key can insert into ignition and trunk and can open trunk, but only goes halfway of side doors.
This is DENSO key, looks like not a fate one. Yet its tongue a little thick and cut a little offset.
1. Any body can tell me, 05 GS300 key, if cut propery, can start the car w/o remote or not?
2. Even I got a correct key later on, can I remove all keys and re-add them? I know new cars need ECU reset not sure mine. Said ECU reset is costy and can only done by dealer.

 

Hey mate, did you program the key with the engine too? Because there are two procedures that can program the key.
1 procedure programs the body modules to except the keyless entry part and the other procedure is to program the engine ecu to your key transponder.

 

Lexus Dealer here in Central Florida start use a key master. Dealer call this guy and this person do all the programming.