Daughter took her Tucson to O’Reilly’s to get battery changed. When they put new battery in an alarm started going off, car wouldn’t start, dash lights flashing—total lock down. Tried to put old battery back in. Same reaction. Now car is just stuck at O’Reilly’s after an hour of trying various googled solutions. Help!

 

To work on vehicles these days , a capable scan tool IS REQUIRED and how to use it.
The vehicle needs to be updated that the battery has been replaced.
Is the remote key function , (Immobilizer) working?

 

I have a key fob that works. Is that what you’re asking? It doesn’t have a remote start feature. Right now, no battery is hooked up and it’s been sitting overnight. If you’re able to give me a step by step that would be great.

 

Al I can suggest is, to install the positive cable onto the battery first , then install the negative cable.

You may need to drive your vehicle a few miles for it to learn your driving habits and schedule the shift points and idle speed.
Let us know how you make out with this, thanks.

 

As soon as I install the negative one the alarm goes off and the car cannot be started.

 

Do you have the remote to silence the alarm?

Did you try to use the remote to silence the alarm when you install the battery cable?

 

Something to try,
From the owner's manual, find the location of the "Horn Relay". Remove it.
Connect the battery and go through the usual motions of locking the vehicle, opening it with the key, inserting the key and turning it on or attempt to start the vehicle. This might reset the system and preventing it from thinking a theft was in progress.