2013 Hyundai Elanta will not start, turn key , new battery, nothing, all lights n dash work, could it be the alarm system OEM

Fob didn't work so the alarm immobiliser was armed and active when the locksmith opened the car - with predictable results.

Fob still not working - broken or needs new battery. Have you fitted a new battery into the fob?

The alarm immobiliser will probably remain armed until the doors have been locked and then unlocked with the fob.

There is a small chance the system can be fooled into thinking it has been disarmed by disconnecting the battery (overnight if poss) and then with the door open and the ignition key in and turned on, when the battery is reconnected it might be possible to start the engine...

OEM is not a specific part. It means original equipment manufacturer. Are you referring to your PCM/ECM? That is the main computer/control module. Is your battery fully charged and charging system working properly? Have you installed any after market equipment or accessories? Automotive electronics can do all sorts of strange stuff when there is a power (battery voltage) problem. A faulty relay is also a possibility.

I’m happy to assist further over the phone at https://www.6ya.com/expert/kim_3202917d7c587455

Not sure about yours, but many will reset by: turn key to "on" and wait 15 minutes or so; shut off, then try to start.

I would return it to the installer

My 2012 Hyundai Elantra Wont Start - CarGurus

www.cargurus.com > Questions > Hyundai > Elantra

CarGurusJul 30, 2013 - My 2012 hyundai Elantra GLS would not start this morning. ... I hit my door unlock on mt Key fab and the doors unlocked fromt here I proceeded start my car.... it and it wont turn over just makes a light click. not like a battery issue. .... But if Istart from the zero position on the starter it doesn't start on the first try ...

No horn / No lights when I lock my car - Hyundai Genesis ...

www.gencoupe.com/.../244433-no-horn-no-lights-when-i-lock-my-car.h...

Mar 30, 2014 - 16 posts - ‎8 authors
I do not know what could have caused this but when i lock my car... ... lock yourdoors with your key fob(might have to hit the lock button twice) ... The alarm/horn should start beeping. ... 2010 Hyundai Genesis Coupe 2.0T R-spec in Karussel White.... My lights flash when I lock it, but the horn doesn't sound.

2013 Hyundai Elantra Engine Won't Turnover, Won't Start ...

www.carcomplaints.com/.../Elantra/.../engine_wont_turnover_wont_start...

The 2013 Hyundai Elantra has 19 complaints for engine won't turnover, won't ...

My problem started after a low battery also. It is a different problem than yours but it might solve your problem. Here is my solution. I believe it's worth a try for the price. All signs point to the Accessory Relay (NOT the Accessory Delay Relay). I replaced the Accessory Relay (Standard Part V13081 RY612). It cost me $15.61 with tax. On the 2004 Ford Escape, it is just to the right of the fuses in the fuse box by the driver's side seat. Three days and all good so far. It is well worth the price to see if this works for you like it worked for me.

I take it the key fob doesn't work Try disconnecting the battery for 30 minutes and see if that will reset the alarm. You may need the key fob to reset.

security system failure will shut everything down
(IT THINKS IT IS BEENING STOLEN) an locked it self out

There is NO possible electrical cause (within REASON) which would create the problem you describe. I assume you tried the Keyless Entry Remote to DIS-ARM the anti-theft system. If the ALARM system was activated, it will stay activated until it's de-activated by the remote (typical design feature). The best SOLUTION is to take vehicle into Hyundai an have the problem diagnosed.

1999 CONCORDE: check the battery terminals probably they are not tight enough...something like that happened to me just the lights turned on and the car seemed to be dead, the battery is still ok since then. I just needed to buy new terminals.