Modern Vespa

OK, this is pissing me off! In the last 3 years and with multiple occurrences, this damn little light keeps acting up. Sometimes it stays lit for months, goes out on it's own, then lights up again! It was off for years, then right after a fill-up, it came on again! Later on restarting, it turned off but came back on two days later.

The owner's manual only identifies it with an arrow and tells us, "Engine Control Warning Light" but no mention of what it's for anywhere in the manual. Dealer says to use premium ( I always do!) and that I must have gotten some bad fuel. Bike runs great with almost 9000 miles on her!

Does anyone have a solution? I'm inclined to believe this is related to the evap canister somehow and would just like to turn it off. Maybe just remove the bulb. Does this light warn of anything other than the evap system?

I live 2 hours from the closest dealer and all they do is reset the code and scratch their heads. HELP!

yes. many possible faults will cause that light. jsut like in a car.

Great thread on rigging up a code reader here: DIY Diagnostic tool for injection Vespa's with MIU ECU

I ended up splicing the power leads to a tender connecter (I might have had to reverse them, you'll want to check polarity on everything if you do something similar and also at all other times).

You can also hook this up to a bluetooth OBD2 scanner. The codes won't give the same description sometimes, but you can cross-reference with a shop manual or forum. Once you know a given code you'll likely see it pop up again, so you at least know what it is when you clear it out. I leave this combo under the seat - basically takes up no space and I can easily clear out codes and fault-check on the fly. It's really been great. The parts that worked for me are linked below - all of these 3rd party things can be kinda YMMV.

Ducati diag cable: https://www.amazon.com/gp/product/B07S85FNV4/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

ODB2 Bluetooth Reader: https://www.amazon.com/gp/product/B06XGB4873/ref=ppx_yo_dt_b_asin_title_o09_s02?ie=UTF8&psc=1

Tender Leads for splicing: https://www.amazon.com/gp/product/B003WDDLTO/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Edit: If anyone buys these don't forget to use the Amazon Smile link in the forum footer!
Double Edit: Uh-oh, looks like the Smile account is down.
Edit Finale: Ignore the above, link good, don't get confused like I did. Jess explained: https://modernvespa.com/forum/post2473517#2473517

Disconnect the evap system.

The fact that the light comes on after filling the tank is a big clue. The evap system is an afterthought for the US market and is not implemented well. Over time, filling the tank can result in a fuel-saturated canister, which then causes the mixture to go rich and the oxygen sensor tells the ecm to lean the mixture. When the ecm has reached the limits of its adjustment and the oxygen sensor is still telling the ecm to lean the mixture more, it usually sets an oxygen sensor code.

This was the exact behavior my GTS exhibited, only mine was so bad it would make the engine idle high or even stall at idle sometimes. Disconnecting the canister and a thorough cleaning of the throttle body & idle passage solved the problem.

Thanks, guys! I will employ BOTH of your suggestions, starting with the disconnect and purge. I've experienced the high idle, etc as well so I suspect this is the problem.