Kia Niro HEV not starting

[Whywhat]

Hi - got a Kia Niro HEV with a key fob that has the old style key to open door and start car. Key fob battery died yesterday so I opened car with physical key. Alarm went off (not sure why) for a short period and then stopped. I didnt drive the car. Today I replaced battery in key fob. Went to open car and now neither of my two key fobs are unlocking car. Opened it again with physical key and tried to turn ignition on with key but car won't start. Its like the battery in car has died but im not sure why as it wasn't like lights were left on or anything. Not sure if some immobiliser has been triggered after alarm went off.

Any idea what I could do to solve it? Thanks for any help

[Vsix and Vtec]

Pop the bonnet and check the voltage at the battery.

Do you get any lights on the dash at all when you turn the key?

[LuS1fer]

How old is it? Batteries don't last forever.

[E-bmw]

Your first operation of the key has likely set off the immobiliser with the alarm, try locking/unlocking a couple of times with the remote, then try again.

ETA.
Failing that see if the manual gives a reset procedure for it or a re-learning for the key fob after battery replacement.

[E-bmw]

CanAm said:

Whywhat said:

Thanks all. I didn't realise there is a 12v battery reset button in the car. Pressed that and everything seems to work again!

Wrong thread. This is about an Astra battery, not your Kia.

Classic case of, "if all else fails, read the instructions".

Well done, you passed.