So I’ve got the 2008 atenza and went to get in it today after driving it a couple of days ago and the keyless door opening isn’t working so opened it manually, once in the car the key isn’t showing up on the dash and when I inserted the key as the back up option it won’t turn to start the car either. Anyone have any clue what’s going on?

 

Dead battery...

 

Try to Jump start the car.

 

I have exactly the same issue. I checked my battery voltage and it was 0 however. It was running absolutely fine 3 days ago.
When I did have a slightly uncharged battery a few weeks ago due to no travelling, the lights still came on, but it needed some juice.
I drove it for 30 mins to charge the battery and keep the current running.
Started up and fine everytime after that.

But now, it doesn't start at all and electrics do not load at all.
I feel it is the immobilizer that is playing up. Anyone know how to reset it on a Gen 2 Mazda6?

 

To fully recharge a battery by driving it, will take about 6hrs constant driving.

1st step would be to fully recharge the battery via a 12v battery charger, followed by a load test of the battery, & test of the charging system.

 

Now it is the weekend, had more time to look into the problem.

It was a nearly dead battery with only 4V flowing through the battery when tested.

Had to charged it to 6V with a portable charger and then jump started it with a working car battery.
Drove around for 45 mins to let the battery do its thing.

Some electrical issues such as my rear window and door mirrors acting awkward but I will need to reset the windows due to battery voltage being v low.

Thankfully radio and console settings are still untouched. Alarm is not playing up either and managed to keep main key central lock details.

My advice is - remove the clamp on the positive terminal. Try to trickle charge it so it has at least 6V running though the battery and then get jump leads to allow the engine to crank up.

Run for 30 mins minimum and drive where possible.
Then allow to sit for another 10-15 mins before trying to switch engine on via normal method.

Great hassle but sorted!