I tried researching this last time it came up. Yeah, if you're from Canada you can run it through that formula (sucks if you didn't look that up before you left home). Nobody in the thread had luck with 00000 or something similar. I didn't really see clear instructions for other countries. It sucks if you need gas outside of business hours.

I had the reverse situation as an American traveling to Iceland when no chip+pin cards were available to me. I picked up the rental car with an almost empty tank. They point me around the corner--the gas station is automated. I start driving the 50km to reykjavik and cross my fingers.

Later in the trip I get into a similar situation of an automated gas station in a desolate area. I waited until a local came by, offered them cash to use their credit card. They seemed suspicious like it was some sort of scam (I dont blame them), but thankfully that worked out.