After inserting the credit card into the self-service fueling machine in Iceland, what PIN should be input, the 6-digit password on the back of the credit card or the transaction password? Some say it's a 4-digit password, what's the deal with that ?

We are ICBC cards. When the machine prompts to enter the PIN code, it is always six digits, whether it is N1 or what seems to be Oli.

What I input is the thinking number on the card. The first four digits.

Buy a pre-paid card and there won't be a problem with self-service refueling.

Four random numbers, I input four zeros.

I lost the first four digits of the transaction password, can you fix it?

I'm using a CMB credit card. When I self-pump gas in Iceland, the password is any 4-digit number.

My card is randomly entered.

The card cannot be entered randomly, I entered the wrong six-digit password and got locked out, then I had to call back to get it unlocked, and entered the six-digit unlock code.