I have a 2009 elantra and when doors r locked and I hit the starter the car lights blink twice and doesn't start! It was a factory install by Hyundai . The car is an automatic . What do I do? Thanks

I have experience with mine that I have to press lock twice then hit the remote start or it will not start.

stand by drivers door then close and open door 3 times with remote then on the last open jump in car and put key in and try to start within 10 secs of getting in the car ,this works with a renault but a hyundai? maybe its worth a try

blown fuse possibly

Fix your car right away by clicking the link I attached https://www.reliable-store.com/products/2004-hyundai-elantra-repair-manual

Check for blown fuses and a faulty main relay.

Sometimes starters come from the factory with shims to make sure there is correct clearance between the starter drive gear and the flywheel, have the person who installed check to see if there was a shim or shims on the old one and wether they put on shims on the new one.

when the alarm is going off, use the key to lock and then unlock the front passenger door lock.

only if you install a remote central locking system.

My ex girlfriend had a factory installed honda remote strt on her vehicle. It was activated by hitting the lock button two times in succession. Some vehicles use a combination of the lock-unlock buttons. try using some combinations on the remote, many "oem" remote starts are installed by aftermarket installers so who knows what they did as a start function, it could also have been changed by the previous owner.

i think that this is to prevent you from locking your keys in the car with the engine running.
Some remote starters have a feature that when the car is running (and in park) you can hit the remote start button twice for one second each - then you can take the key out of the ignition and still have the car running.
At this point....if you would hit the 'lock' button on your door the doors would immediately unlock. However, if you get out of the car and close the door leaving it unlocked and then you hit the 'lock' on your original car remote the doors will lock and stay locked. So now the car is running the doors are locked and you have the keys in your hands. Then you can run into the store or house real quick with your car locked.
Once you come back, you hit 'unlock' on the original car remote. the doors will unlock - you can get it - and then before hitting the brake put the key in the ignition and turn it (dont crank it) as if you had when originally using the remote starter.
Maybe this will work for you.....