Aloha…
changing spark plugs
on Asian 2015 yaris 1.3L automatic…
do i need to disconnect battery? Both cables?
In theory it's safe. The ignition system is de-energized with the ignition off.
However, I think that disconnecting the battery is a good habit to get into. We are only human, and humans make mistakes, and unpredictable situations do happen, and then ... "OOPS. I should have disconnected the battery first". And now you have an additional problem to fix. It's happened to me a couple of times. Just do it. It only takes a minute or two and you have peace of mind.
I've never heard of anything like that, in over 50 years I've never disconnected a battery when changing spark plugs, just made sure the ignition was off. Maybe your car requires it for some reason? You'd need to consult the factory shop manual.
hi it depends on if you want to have a short disconect both + and - do be safe
All the references I’ve seen say yes, but it will be interesting to see if anyone here explains why.
It's probably just an extra safety precaution in case the engine decides to turn itself on
😂