So I pretty much just replace the battery on my key and now when I hold the trunk release button the trunk does not open anymore, press unlock button to unlock all doors have to be press/hold a bit in order to fully unlock all doors. Everything was fine before change of battery, anyone know what could be the issue? Can I reprogram it myself or do I need some special equipment?

 

if everything was fine before the battery why did you replace it?

The keys do break eventually so if it broke and replacing the battery didn't work then it might be the remote itself.

 

First check the contacts inside the key housing to make sure they are properly contacting the battery and that nothing inside is broken. I had to bend one of the battery contacts in one of my wife's "book lights" just last week so that it made good contact with a similar flat battery.

Or maybe you got a bad new battery. You wouldn't be the first.

 

Disconnect the negative wire from the battery and connect back after at least a minute.
This usually reset/reprogram everything to default factory setting. if you have an aftermarket keyless entry you will have to reprogram it manually.

This is just my guess since im not to familiar with lexus yet (just got an 96 ls 400, week ago).

 

Everything was good as in the buttons was fine press and work but the battery was dying on it So I replace it. Ill check the contact today and will do the disconnect the negative and see how it goes

 

that's not true for the OEM keys. The oem alarm pairing information is persistent, and will only reset if you intentionally clear the rom.

i've had my car batteryless for a week and didnt have to re-pair the alarm or immobilizer.

 

Okay so I tried all the suggestions ya stated and still nothing. Um on the 98 is there a trunk release button/switch in the glove compartment as well? I open to look and saw no button