Key Not Working At All

[alexharvey]

Hey everyone,

I have a strange issue with my 2018 Jazz. The battery ran flat due to leaving the interior lights on. The key/fob would not unlock the car through the remote, and the key could not unlock the car using the keyhole. I assume that is electronic and requires to recognize the key nearby when the lock is turned, but with the battery dead the immobilizer doesn't work (correct me if I'm wrong.)

So I hooked up a spare battery from underneath to the alternator charge wire and chassis which made the key fob work and I unlocked the car. I then charged the battery. I then proceed to leave the lights on again and run the battery flat again (I don't want to talk about that please haha).

So I try and hook up a battery again, but this time the key doesn't work, not with the remote or in the door. I know the power was getting through the car because the interior lights came on bright.

Does this mean the key has come unpaired from the immboliser? Do I need to get a new key paired or repair this one? Thanks in advance.

[ColinB]

Maybe the battery in the key fob has died? Changing it would be a simple thing to try before getting into more complicated stuff.

Re. this:

... the key could not unlock the car using the keyhole. I assume that is electronic ...

Never had to do this myself, but I always thought that this was an old-fashioned mechanical unlocking procedure specifically intended to be used when batteries were flat. So I’m a bit surprised that this didn’t work. At the risk of stating the blindingly obvious, were you using the right key?