I've just had an FI episode with my 2018 DL650. Dropped the bike at low speed whilst manoeuvring at low speed (sigh). The left handlebar copped the bang and I found the hand guard had been pushed up.
I pulled it back into position and started the bike - all good. As we set off home the engine cut-out for no apparent reason, but started again and seemed fine. A few minutes later I noticed the FI indication alternating with the Odometer and the Engine light was on steadily. Pulled over to give the bike a quick once-over and found nothing wrong, so we set off home by the shortest route.
Got home and googled how to get into dealer mode and found I had C65 - engine idle fault. Some sites mentioned it related to TPS and GPS faults, but another site mentioned the Clutch sensor and I thought AHA! - the clutch sensor may have been bumped by the hand-guard. Sure enough - there it was pushed off toward the front of the bike so that the sensor was no longer aligned to the clutch lever. (It's only held by 1 screw and a plastic locator that sits in a hole near the clutch lever). I put everything back as it should be and started the bike for a short time, then put the bike into dealer mode with the engine stopped - FI was still there and C65.
A bit more googling, and this thread indicated to me that I needed to cycle through dealer mode with a WARM ENGINE. Rode to work this morning - took the seat off, while the engine was still running and put her into dealer mode - C65. Switched off the engine, then turned the ignition on again and got - C00 and no FI/engine light. A great relief to know that these things can be fixed without resorting to going to the dealer or
buying "fault clearing" gadgets
Thanks to all who came before me, I trust my tail lights will help the next rider.